diff --git a/README.md b/README.md
index 9c41e644..7e3a213f 100644
--- a/README.md
+++ b/README.md
@@ -76,7 +76,7 @@ All options are case-sensitive.
 \* Note that oxipng is not a brute-force optimizer. This means that while higher optimization levels
 are almost always better or equal to lower levels, this is not guaranteed and it is possible in
 rare circumstances that a lower level may give a marginally smaller output. Similarly, using Zopfli
-compression (`-Z`) is not guaranteed to always be better than without.
+compression (`-z`) is not guaranteed to always be better than without.
 
 ## Git integration via [pre-commit]
 
diff --git a/benches/interlacing.rs b/benches/interlacing.rs
index 055734bc..fbe6467d 100644
--- a/benches/interlacing.rs
+++ b/benches/interlacing.rs
@@ -13,7 +13,7 @@ fn interlacing_16_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -21,7 +21,7 @@ fn interlacing_8_bits(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_8_should_be_rgb_8.png"));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -31,7 +31,7 @@ fn interlacing_4_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -41,7 +41,7 @@ fn interlacing_2_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -51,7 +51,7 @@ fn interlacing_1_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::Adam7));
+    b.iter(|| png.raw.change_interlacing(true));
 }
 
 #[bench]
@@ -61,7 +61,7 @@ fn deinterlacing_16_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -71,7 +71,7 @@ fn deinterlacing_8_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -81,7 +81,7 @@ fn deinterlacing_4_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -91,7 +91,7 @@ fn deinterlacing_2_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
 
 #[bench]
@@ -101,5 +101,5 @@ fn deinterlacing_1_bits(b: &mut Bencher) {
     ));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
-    b.iter(|| png.raw.change_interlacing(Interlacing::None));
+    b.iter(|| png.raw.change_interlacing(false));
 }
diff --git a/benches/zopfli.rs b/benches/zopfli.rs
index 345a71ab..a189a35f 100644
--- a/benches/zopfli.rs
+++ b/benches/zopfli.rs
@@ -3,20 +3,18 @@
 extern crate oxipng;
 extern crate test;
 
-use std::{num::NonZeroU8, path::PathBuf};
+use std::path::PathBuf;
 
 use oxipng::{internal_tests::*, *};
 use test::Bencher;
 
-const DEFAULT_ZOPFLI_ITERATIONS: NonZeroU8 = NonZeroU8::new(15).unwrap();
-
 #[bench]
 fn zopfli_16_bits_strategy_0(b: &mut Bencher) {
     let input = test::black_box(PathBuf::from("tests/files/rgb_16_should_be_rgb_16.png"));
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -26,7 +24,7 @@ fn zopfli_8_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -38,7 +36,7 @@ fn zopfli_4_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -50,7 +48,7 @@ fn zopfli_2_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
 
@@ -62,6 +60,6 @@ fn zopfli_1_bits_strategy_0(b: &mut Bencher) {
     let png = PngData::new(&input, &Options::default()).unwrap();
 
     b.iter(|| {
-        zopfli_deflate(png.raw.data.as_ref(), DEFAULT_ZOPFLI_ITERATIONS).ok();
+        zopfli_deflate(png.raw.data.as_ref(), ZopfliOptions::default()).ok();
     });
 }
diff --git a/src/cli.rs b/src/cli.rs
index 800da204..8977cf99 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -1,6 +1,6 @@
-use std::path::PathBuf;
+use std::{num::NonZeroU64, path::PathBuf};
 
-use clap::{Arg, ArgAction, Command, value_parser};
+use clap::{Arg, ArgAction, Command, builder::ArgPredicate, value_parser};
 
 include!("display_chunks.rs");
 
@@ -97,10 +97,10 @@ Note that this will not preserve the directory structure of the input files when
                 .action(ArgAction::SetTrue),
         )
         .arg(
-            Arg::new("pretend")
+            Arg::new("dry-run")
                 .help("Do not write any files, only show compression results")
-                .short('P')
-                .long("pretend")
+                .short('d')
+                .long("dry-run")
                 .action(ArgAction::SetTrue),
         )
         .arg(
@@ -163,24 +163,23 @@ transformation and may be unsuitable for some applications.")
                 .action(ArgAction::SetTrue),
         )
         .arg(
-            // Note: The default value is not explicitly set here, as it is dependant on the `--nx` flag.
             Arg::new("interlace")
-                .help("Set PNG interlacing type (0, 1, keep) [default: 0]")
+                .help("Set PNG interlacing (off, on, keep)")
                 .long_help("\
-Set the PNG interlacing type, where <type> is one of:
+Set the PNG interlacing mode, where <mode> is one of:
 
-    0     =>  Remove interlacing from all images that are processed
-    1     =>  Apply Adam7 interlacing on all images that are processed
-    keep  =>  Keep the existing interlacing type of each image
+    off   =>  Remove interlacing from all images that are processed
+    on    =>  Apply Adam7 interlacing on all images that are processed
+    keep  =>  Keep the existing interlacing mode of each image
 
 Note that interlacing can add 25-50% to the size of an optimized image. Only use it if you \
-believe the benefits outweigh the costs for your use case.
-
-[default: 0]")
+believe the benefits outweigh the costs for your use case.")
                 .short('i')
                 .long("interlace")
-                .value_name("type")
-                .value_parser(["0", "1", "keep"])
+                .value_name("mode")
+                .value_parser(["off", "on", "keep", "0", "1"])
+                .default_value("off")
+                .default_value_if("no-reductions", ArgPredicate::IsPresent, "keep")
                 .hide_possible_values(true),
         )
         .arg(
@@ -325,7 +324,8 @@ be processed successfully.")
                 .long_help("\
 Use the much slower but stronger Zopfli compressor for main compression trials. \
 Recommended use is with '-o max' and '--fast'.")
-                .short('Z')
+                .short('z')
+                .short_alias('Z') // Kept for backwards compatibility
                 .long("zopfli")
                 .action(ArgAction::SetTrue),
         )
@@ -338,7 +338,18 @@ speed up compression for large files. This option requires '--zopfli' to be set.
                 .long("zi")
                 .value_name("iterations")
                 .default_value("15")
-                .value_parser(1..=255)
+                .value_parser(value_parser!(NonZeroU64))
+                .requires("zopfli"),
+        )
+        .arg(
+            Arg::new("iterations-without-improvement")
+                .hide_short_help(true)
+                .long_help("\
+Stop Zopfli compression after this number of iterations without improvement. Use this in \
+conjunction with a high value for '--zi' to achieve better compression in reasonable time.")
+                .long("ziwi")
+                .value_name("iterations")
+                .value_parser(value_parser!(NonZeroU64))
                 .requires("zopfli"),
         )
         .arg(
diff --git a/src/colors.rs b/src/colors.rs
index a5365d2c..e1c49724 100644
--- a/src/colors.rs
+++ b/src/colors.rs
@@ -116,7 +116,7 @@ impl TryFrom<u8> for BitDepth {
             4 => Ok(Self::Four),
             8 => Ok(Self::Eight),
             16 => Ok(Self::Sixteen),
-            _ => Err(PngError::new("Unexpected bit depth")),
+            _ => Err(PngError::InvalidData),
         }
     }
 }
diff --git a/src/deflate/deflater.rs b/src/deflate/deflater.rs
index 9ba19f59..1133a44c 100644
--- a/src/deflate/deflater.rs
+++ b/src/deflate/deflater.rs
@@ -22,7 +22,7 @@ pub fn inflate(data: &[u8], out_size: usize) -> PngResult<Vec<u8>> {
         .zlib_decompress(data, &mut dest)
         .map_err(|err| match err {
             DecompressionError::BadData => PngError::InvalidData,
-            DecompressionError::InsufficientSpace => PngError::new("inflated data too long"),
+            DecompressionError::InsufficientSpace => PngError::InflatedDataTooLong(out_size),
         })?;
     dest.truncate(len);
     Ok(dest)
diff --git a/src/deflate/mod.rs b/src/deflate/mod.rs
index b8b4ceab..1ae49bcb 100644
--- a/src/deflate/mod.rs
+++ b/src/deflate/mod.rs
@@ -1,19 +1,19 @@
 mod deflater;
-#[cfg(feature = "zopfli")]
-use std::num::NonZeroU8;
-use std::{fmt, fmt::Display};
-
 pub use deflater::{crc32, deflate, inflate};
 
 use crate::{PngError, PngResult};
+use std::{fmt, fmt::Display};
+
 #[cfg(feature = "zopfli")]
 mod zopfli_oxipng;
 #[cfg(feature = "zopfli")]
+pub use zopfli::Options as ZopfliOptions;
+#[cfg(feature = "zopfli")]
 pub use zopfli_oxipng::deflate as zopfli_deflate;
 
 /// DEFLATE algorithms supported by oxipng (for use in [`Options`][crate::Options])
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
-pub enum Deflaters {
+pub enum Deflater {
     /// Use libdeflater.
     Libdeflater {
         /// Which compression level to use on the file (0-12)
@@ -21,20 +21,15 @@ pub enum Deflaters {
     },
     #[cfg(feature = "zopfli")]
     /// Use the better but slower Zopfli implementation
-    Zopfli {
-        /// The number of compression iterations to do. 15 iterations are fine
-        /// for small files, but bigger files will need to be compressed with
-        /// less iterations, or else they will be too slow.
-        iterations: NonZeroU8,
-    },
+    Zopfli(ZopfliOptions),
 }
 
-impl Deflaters {
+impl Deflater {
     pub(crate) fn deflate(self, data: &[u8], max_size: Option<usize>) -> PngResult<Vec<u8>> {
         let compressed = match self {
             Self::Libdeflater { compression } => deflate(data, compression, max_size)?,
             #[cfg(feature = "zopfli")]
-            Self::Zopfli { iterations } => zopfli_deflate(data, iterations)?,
+            Self::Zopfli(options) => zopfli_deflate(data, options)?,
         };
         if let Some(max) = max_size {
             if compressed.len() > max {
@@ -45,13 +40,13 @@ impl Deflaters {
     }
 }
 
-impl Display for Deflaters {
+impl Display for Deflater {
     #[inline]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Self::Libdeflater { compression } => write!(f, "zc = {compression}"),
             #[cfg(feature = "zopfli")]
-            Self::Zopfli { iterations } => write!(f, "zopfli, zi = {iterations}"),
+            Self::Zopfli(options) => write!(f, "zopfli, zi = {}", options.iteration_count),
         }
     }
 }
diff --git a/src/deflate/zopfli_oxipng.rs b/src/deflate/zopfli_oxipng.rs
index b77e3164..c66a0c65 100644
--- a/src/deflate/zopfli_oxipng.rs
+++ b/src/deflate/zopfli_oxipng.rs
@@ -1,13 +1,7 @@
-use std::num::NonZeroU8;
-
 use crate::{PngError, PngResult};
 
-pub fn deflate(data: &[u8], iterations: NonZeroU8) -> PngResult<Vec<u8>> {
+pub fn deflate(data: &[u8], options: zopfli::Options) -> PngResult<Vec<u8>> {
     let mut output = Vec::with_capacity(data.len());
-    let options = zopfli::Options {
-        iteration_count: iterations.into(),
-        ..Default::default()
-    };
     // Since Rust v1.74, passing &[u8] directly into zopfli causes a regression in compressed size
     // for some files. Wrapping the slice in another Read implementer such as Box fixes it for now.
     match zopfli::compress(options, zopfli::Format::Zlib, Box::new(data), &mut output) {
diff --git a/src/error.rs b/src/error.rs
index 2c7d88a9..0d022812 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -2,20 +2,22 @@ use std::{error::Error, fmt};
 
 use crate::colors::{BitDepth, ColorType};
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 #[non_exhaustive]
 pub enum PngError {
-    DeflatedDataTooLong(usize),
-    TimedOut,
-    NotPNG,
-    APNGNotSupported,
     APNGOutOfOrder,
-    InvalidData,
-    TruncatedData,
-    ChunkMissing(&'static str),
-    InvalidDepthForType(BitDepth, ColorType),
-    IncorrectDataLength(usize, usize),
     C2PAMetadataPreventsChanges,
+    ChunkMissing(&'static str),
+    CRCMismatch([u8; 4]),
+    DeflatedDataTooLong(usize),
+    IncorrectDataLength(usize, usize),
+    InflatedDataTooLong(usize),
+    InvalidData,
+    InvalidDepthForType(BitDepth, ColorType),
+    NotPNG,
+    ReadFailed(String, std::io::Error),
+    TruncatedData,
+    WriteFailed(String, std::io::Error),
     Other(Box<str>),
 }
 
@@ -26,26 +28,32 @@ impl fmt::Display for PngError {
     #[cold]
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
-            PngError::DeflatedDataTooLong(_) => f.write_str("deflated data too long"),
-            PngError::TimedOut => f.write_str("timed out"),
-            PngError::NotPNG => f.write_str("Invalid header detected; Not a PNG file"),
-            PngError::InvalidData => f.write_str("Invalid data found; unable to read PNG file"),
-            PngError::TruncatedData => {
-                f.write_str("Missing data in the file; the file is truncated")
-            }
-            PngError::APNGNotSupported => f.write_str("APNG files are not (yet) supported"),
             PngError::APNGOutOfOrder => f.write_str("APNG chunks are out of order"),
+            PngError::C2PAMetadataPreventsChanges => f.write_str(
+                "The image contains C2PA manifest that would be invalidated by any file changes",
+            ),
             PngError::ChunkMissing(s) => write!(f, "Chunk {s} missing or empty"),
-            PngError::InvalidDepthForType(d, ref c) => {
-                write!(f, "Invalid bit depth {d} for color type {c}")
-            }
+            PngError::CRCMismatch(ref c) => write!(
+                f,
+                "CRC mismatch in {} chunk; May be recoverable by using --fix",
+                String::from_utf8_lossy(c)
+            ),
+            PngError::DeflatedDataTooLong(_) => f.write_str("Deflated data too long"),
             PngError::IncorrectDataLength(l1, l2) => write!(
                 f,
                 "Data length {l1} does not match the expected length {l2}"
             ),
-            PngError::C2PAMetadataPreventsChanges => f.write_str(
-                "The image contains C2PA manifest that would be invalidated by any file changes",
-            ),
+            PngError::InflatedDataTooLong(_) => f.write_str("Inflated data too long"),
+            PngError::InvalidData => f.write_str("Invalid data found; unable to read PNG file"),
+            PngError::InvalidDepthForType(d, ref c) => {
+                write!(f, "Invalid bit depth {d} for color type {c}")
+            }
+            PngError::NotPNG => f.write_str("Invalid header detected; Not a PNG file"),
+            PngError::ReadFailed(ref s, ref e) => write!(f, "Failed to read from {s}: {e}"),
+            PngError::TruncatedData => {
+                f.write_str("Missing data in the file; the file is truncated")
+            }
+            PngError::WriteFailed(ref s, ref e) => write!(f, "Failed to write to {s}: {e}"),
             PngError::Other(ref s) => f.write_str(s),
         }
     }
diff --git a/src/evaluate.rs b/src/evaluate.rs
index 9463cf6b..d5c38e85 100644
--- a/src/evaluate.rs
+++ b/src/evaluate.rs
@@ -10,7 +10,7 @@ use std::sync::{
 
 #[cfg(feature = "parallel")]
 use crossbeam_channel::{Receiver, Sender, unbounded};
-use deflate::Deflaters;
+use deflate::Deflater;
 use indexmap::IndexSet;
 use log::trace;
 use rayon::prelude::*;
@@ -50,7 +50,7 @@ impl Candidate {
 pub(crate) struct Evaluator {
     deadline: Arc<Deadline>,
     filters: IndexSet<FilterStrategy>,
-    deflater: Deflaters,
+    deflater: Deflater,
     optimize_alpha: bool,
     final_round: bool,
     nth: AtomicUsize,
@@ -68,7 +68,7 @@ impl Evaluator {
     pub fn new(
         deadline: Arc<Deadline>,
         filters: IndexSet<FilterStrategy>,
-        deflater: Deflaters,
+        deflater: Deflater,
         optimize_alpha: bool,
         final_round: bool,
     ) -> Self {
diff --git a/src/headers.rs b/src/headers.rs
index db48f15b..3e3f6a99 100644
--- a/src/headers.rs
+++ b/src/headers.rs
@@ -3,12 +3,11 @@ use log::{debug, trace, warn};
 use rgb::{RGB16, RGBA8};
 
 use crate::{
-    Deflaters, Options, PngResult,
+    Deflater, Options, PngResult,
     colors::{BitDepth, ColorType},
     deflate::{crc32, inflate},
     display_chunks::DISPLAY_CHUNKS,
     error::PngError,
-    interlace::Interlacing,
 };
 
 #[derive(Debug, Clone)]
@@ -22,8 +21,8 @@ pub struct IhdrData {
     pub color_type: ColorType,
     /// The bit depth of the image
     pub bit_depth: BitDepth,
-    /// The interlacing mode of the image
-    pub interlaced: Interlacing,
+    /// Whether the image is interlaced
+    pub interlaced: bool,
 }
 
 impl IhdrData {
@@ -45,7 +44,7 @@ impl IhdrData {
             (w * bpp).div_ceil(8) * h
         }
 
-        if self.interlaced == Interlacing::None {
+        if !self.interlaced {
             bitmap_size(bpp, w, h) + h
         } else {
             let mut size = bitmap_size(bpp, (w + 7) >> 3, (h + 7) >> 3) + ((h + 7) >> 3);
@@ -173,10 +172,7 @@ pub fn parse_next_chunk<'a>(
 
     let chunk_bytes = &byte_data[chunk_start..chunk_start + 4 + length as usize];
     if !fix_errors && crc32(chunk_bytes) != crc {
-        return Err(PngError::new(&format!(
-            "CRC Mismatch in {} chunk; May be recoverable by using --fix",
-            String::from_utf8_lossy(chunk_name)
-        )));
+        return Err(PngError::CRCMismatch(chunk_name.try_into().unwrap()));
     }
 
     let name: [u8; 4] = chunk_name.try_into().unwrap();
@@ -209,12 +205,16 @@ pub fn parse_ihdr_chunk(
             },
             4 => ColorType::GrayscaleAlpha,
             6 => ColorType::RGBA,
-            _ => return Err(PngError::new("Unexpected color type in header")),
+            _ => return Err(PngError::InvalidData),
         },
         bit_depth: byte_data[8].try_into()?,
         width: read_be_u32(&byte_data[0..4]),
         height: read_be_u32(&byte_data[4..8]),
-        interlaced: interlaced.try_into()?,
+        interlaced: match interlaced {
+            0 => false,
+            1 => true,
+            _ => return Err(PngError::InvalidData),
+        },
     })
 }
 
@@ -223,7 +223,7 @@ fn palette_to_rgba(
     palette_data: Option<Vec<u8>>,
     trns_data: Option<Vec<u8>>,
 ) -> Result<Vec<RGBA8>, PngError> {
-    let palette_data = palette_data.ok_or_else(|| PngError::new("no palette in indexed image"))?;
+    let palette_data = palette_data.ok_or(PngError::ChunkMissing("PLTE"))?;
     let mut palette: Vec<_> = palette_data
         .chunks_exact(3)
         .map(|color| RGBA8::new(color[0], color[1], color[2], 255))
@@ -276,7 +276,7 @@ pub fn extract_icc(iccp: &Chunk) -> Option<Vec<u8>> {
 }
 
 /// Make an iCCP chunk by compressing the ICC profile
-pub fn make_iccp(icc: &[u8], deflater: Deflaters, max_size: Option<usize>) -> PngResult<Chunk> {
+pub fn make_iccp(icc: &[u8], deflater: Deflater, max_size: Option<usize>) -> PngResult<Chunk> {
     let mut compressed = deflater.deflate(icc, max_size)?;
     let mut data = Vec::with_capacity(compressed.len() + 5);
     data.extend(b"icc"); // Profile name - generally unused, can be anything
@@ -348,7 +348,7 @@ pub fn preprocess_chunks(aux_chunks: &mut Vec<Chunk>, opts: &mut Options) {
             } else if opts.idat_recoding {
                 // Try recompressing the profile
                 let cur_len = aux_chunks[iccp_idx].data.len();
-                if let Ok(iccp) = make_iccp(&icc, opts.deflate, Some(cur_len - 1)) {
+                if let Ok(iccp) = make_iccp(&icc, opts.deflater, Some(cur_len - 1)) {
                     debug!(
                         "Recompressed iCCP chunk: {} ({} bytes decrease)",
                         iccp.data.len(),
diff --git a/src/interlace.rs b/src/interlace.rs
index 7b4f2f5e..23f0dd27 100644
--- a/src/interlace.rs
+++ b/src/interlace.rs
@@ -1,42 +1,6 @@
-use std::{fmt, fmt::Display};
-
 use bitvec::prelude::*;
 
-use crate::{PngError, headers::IhdrData, png::PngImage};
-
-/// Whether to enable progressive rendering. See [`Options`][crate::Options])
-#[repr(u8)]
-#[derive(Debug, PartialEq, Eq, Clone, Copy)]
-pub enum Interlacing {
-    /// Makes images load top to bottom.
-    None,
-    /// Makes it possible to render partially-loaded images at lower resolution. Usually increases file sizes.
-    Adam7,
-}
-
-impl TryFrom<u8> for Interlacing {
-    type Error = PngError;
-
-    fn try_from(value: u8) -> Result<Self, Self::Error> {
-        match value {
-            0 => Ok(Self::None),
-            1 => Ok(Self::Adam7),
-            _ => Err(PngError::new("Unexpected interlacing in header")),
-        }
-    }
-}
-
-impl Display for Interlacing {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        Display::fmt(
-            match self {
-                Self::None => "non-interlaced",
-                Self::Adam7 => "interlaced",
-            },
-            f,
-        )
-    }
-}
+use crate::{headers::IhdrData, png::PngImage};
 
 #[must_use]
 pub fn interlace_image(png: &PngImage) -> PngImage {
@@ -89,7 +53,7 @@ pub fn interlace_image(png: &PngImage) -> PngImage {
         data: output,
         ihdr: IhdrData {
             color_type: png.ihdr.color_type.clone(),
-            interlaced: Interlacing::Adam7,
+            interlaced: true,
             ..png.ihdr
         },
     }
@@ -103,7 +67,7 @@ pub fn deinterlace_image(png: &PngImage) -> PngImage {
         },
         ihdr: IhdrData {
             color_type: png.ihdr.color_type.clone(),
-            interlaced: Interlacing::None,
+            interlaced: false,
             ..png.ihdr
         },
     }
diff --git a/src/lib.rs b/src/lib.rs
index d11c3ae3..edbf33db 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -41,13 +41,14 @@ use log::{debug, info, trace, warn};
 use rayon::prelude::*;
 pub use rgb::{RGB16, RGBA8};
 
+#[cfg(feature = "zopfli")]
+pub use crate::deflate::ZopfliOptions;
 pub use crate::{
     colors::{BitDepth, ColorType},
-    deflate::Deflaters,
+    deflate::Deflater,
     error::PngError,
     filters::{FilterStrategy, RowFilter},
     headers::StripChunks,
-    interlace::Interlacing,
     options::{InFile, Options, OutFile},
 };
 use crate::{
@@ -130,7 +131,7 @@ impl RawImage {
                     height,
                     color_type,
                     bit_depth,
-                    interlaced: Interlacing::None,
+                    interlaced: false,
                 },
                 data,
             }),
@@ -146,7 +147,7 @@ impl RawImage {
     /// Add an ICC profile for the image
     pub fn add_icc_profile(&mut self, data: &[u8]) {
         // Compress with fastest compression level - will be recompressed during optimization
-        let deflater = Deflaters::Libdeflater { compression: 1 };
+        let deflater = Deflater::Libdeflater { compression: 1 };
         if let Ok(iccp) = make_iccp(data, deflater, None) {
             self.aux_chunks.push(iccp);
         }
@@ -181,7 +182,9 @@ impl RawImage {
 }
 
 /// Perform optimization on the input file using the options provided
-pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<()> {
+///
+/// Returns the original and optimized file sizes
+pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(usize, usize)> {
     // Read in the file and try to decode as PNG.
     info!("Processing: {input}");
 
@@ -218,7 +221,7 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
             let mut data = Vec::new();
             stdin()
                 .read_to_end(&mut data)
-                .map_err(|e| PngError::new(&format!("Error reading stdin: {e}")))?;
+                .map_err(|e| PngError::ReadFailed("stdin".into(), e))?;
             data
         }
     };
@@ -230,14 +233,14 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
 
     let in_length = in_data.len();
 
-    if is_fully_optimized(in_data.len(), optimized_output.len(), opts) {
+    if is_fully_optimized(in_length, optimized_output.len(), opts) {
         match (output, input) {
             // If output path is None, it also means same as the input path
             (OutFile::Path { path, .. }, InFile::Path(input_path))
                 if path.as_ref().is_none_or(|p| p == input_path) =>
             {
                 info!("{input}: Could not optimize further, no change written");
-                return Ok(());
+                return Ok((in_length, in_length));
             }
             _ => {
                 optimized_output = in_data;
@@ -261,26 +264,21 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
 
     match (output, input) {
         (OutFile::None, _) => {
-            info!("{savings}: Running in pretend mode, no output");
+            info!("{savings}: Dry run, no output");
         }
         (&OutFile::StdOut, _) | (&OutFile::Path { path: None, .. }, &InFile::StdIn) => {
             let mut buffer = BufWriter::new(stdout());
             buffer
                 .write_all(&optimized_output)
-                .map_err(|e| PngError::new(&format!("Unable to write to stdout: {e}")))?;
+                .map_err(|e| PngError::WriteFailed("stdout".into(), e))?;
         }
         (OutFile::Path { path, .. }, _) => {
             let output_path = path
                 .as_ref()
                 .map(|p| p.as_path())
                 .unwrap_or_else(|| input.path().unwrap());
-            let out_file = File::create(output_path).map_err(|err| {
-                PngError::new(&format!(
-                    "Unable to write to file {}: {}",
-                    output_path.display(),
-                    err
-                ))
-            })?;
+            let out_file = File::create(output_path)
+                .map_err(|err| PngError::WriteFailed(output_path.display().to_string(), err))?;
             if let Some(metadata_input) = &opt_metadata_preserved {
                 copy_permissions(metadata_input, &out_file)?;
             }
@@ -290,13 +288,7 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
                 .write_all(&optimized_output)
                 // flush BufWriter so IO errors don't get swallowed silently on close() by drop!
                 .and_then(|()| buffer.flush())
-                .map_err(|e| {
-                    PngError::new(&format!(
-                        "Unable to write to {}: {}",
-                        output_path.display(),
-                        e
-                    ))
-                })?;
+                .map_err(|e| PngError::WriteFailed(output_path.display().to_string(), e))?;
             // force drop and thereby closing of file handle before modifying any timestamp
             std::mem::drop(buffer);
             if let Some(metadata_input) = &opt_metadata_preserved {
@@ -305,7 +297,7 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
             info!("{}: {}", savings, output_path.display());
         }
     }
-    Ok(())
+    Ok((in_length, optimized_output.len()))
 }
 
 /// Perform optimization on the input file using the options provided, where the file is already
@@ -395,7 +387,7 @@ fn optimize_png(
         );
     }
 
-    if opts.interlace == Some(Interlacing::Adam7) && png.raw.ihdr.interlaced != Interlacing::Adam7 {
+    if opts.interlace == Some(true) && !png.raw.ihdr.interlaced {
         warn!(
             "Interlacing was not enabled as it would result in a larger file. To override this, use `--force`."
         );
@@ -420,16 +412,16 @@ fn optimize_raw(
     // 8 is a little slower but not noticeably when used only for reductions (o3 and higher)
     // 9 is not appreciably better than 8
     // 10 and higher are quite slow - good for filters but only good for reductions if matching the main zc level
-    let compression = match opts.deflate {
-        Deflaters::Libdeflater { compression } => {
+    let compression = match opts.deflater {
+        Deflater::Libdeflater { compression } => {
             if opts.fast_evaluation { 7 } else { 8 }.min(compression)
         }
         _ => 8,
     };
-    let eval_deflater = Deflaters::Libdeflater { compression };
+    let eval_deflater = Deflater::Libdeflater { compression };
     // If only one filter is selected, use this for evaluations
-    let eval_filters = if opts.filter.len() == 1 {
-        opts.filter.clone()
+    let eval_filters = if opts.filters.len() == 1 {
+        opts.filters.clone()
     } else {
         // None and Bigrams work well together, especially for alpha reductions
         indexset! {FilterStrategy::NONE, FilterStrategy::Bigrams}
@@ -440,7 +432,7 @@ fn optimize_raw(
         eval_filters.clone(),
         eval_deflater,
         false,
-        opts.deflate == eval_deflater,
+        opts.deflater == eval_deflater,
     );
     let mut new_image = perform_reductions(image.clone(), opts, &deadline, &eval);
     let eval_result = eval.get_best_candidate();
@@ -465,7 +457,7 @@ fn optimize_raw(
             eval_filters,
             eval_deflater,
         );
-        (result?, opts.deflate)
+        (result?, opts.deflater)
     } else {
         // If idat_recoding is off and reductions were attempted but ended up choosing the baseline,
         // we should still check if the evaluator compressed the baseline smaller than the original.
@@ -490,9 +482,9 @@ fn perform_trials(
     max_size: Option<usize>,
     mut eval_result: Option<Candidate>,
     eval_filters: IndexSet<FilterStrategy>,
-    eval_deflater: Deflaters,
+    eval_deflater: Deflater,
 ) -> Option<Candidate> {
-    let mut filters = opts.filter.clone();
+    let mut filters = opts.filters.clone();
     let fast_eval = opts.fast_evaluation && (filters.len() > 1 || eval_result.is_some());
     if fast_eval {
         // Perform a fast evaluation of selected filters followed by a single main compression trial
@@ -509,7 +501,7 @@ fn perform_trials(
                 filters,
                 eval_deflater,
                 opts.optimize_alpha,
-                opts.deflate == eval_deflater,
+                opts.deflater == eval_deflater,
             );
             if let Some(result) = &eval_result {
                 eval.set_best_size(result.estimated_output_size);
@@ -525,9 +517,9 @@ fn perform_trials(
 
         if result.idat_data.is_none() {
             // Compress with the main deflater
-            debug!("Trying filter {} with {}", result.filter, opts.deflate);
+            debug!("Trying filter {} with {}", result.filter, opts.deflater);
             let (data, _) = image.filter_image(result.filter_used.clone(), opts.optimize_alpha);
-            match opts.deflate.deflate(&data, max_size) {
+            match opts.deflater.deflate(&data, max_size) {
                 Ok(idat_data) => {
                     result.estimated_output_size = result.image.estimated_output_size(&idat_data);
                     result.idat_data = Some(idat_data);
@@ -555,8 +547,8 @@ fn perform_trials(
         }
     }
 
-    debug!("Trying {} filters with {}", filters.len(), opts.deflate);
-    let eval = Evaluator::new(deadline, filters, opts.deflate, opts.optimize_alpha, true);
+    debug!("Trying {} filters with {}", filters.len(), opts.deflater);
+    let eval = Evaluator::new(deadline, filters, opts.deflater, opts.optimize_alpha, true);
     if let Some(max_size) = max_size {
         eval.set_best_size(max_size);
     }
@@ -616,9 +608,14 @@ impl Deadline {
 
 /// Display the format of the image data
 fn report_format(prefix: &str, png: &PngImage) {
+    let interlaced = if png.ihdr.interlaced {
+        "interlaced"
+    } else {
+        "non-interlaced"
+    };
     debug!(
         "{}{}-bit {}, {}",
-        prefix, png.ihdr.bit_depth, png.ihdr.color_type, png.ihdr.interlaced
+        prefix, png.ihdr.bit_depth, png.ihdr.color_type, interlaced
     );
 }
 
@@ -648,7 +645,7 @@ fn recompress_frames(
             let image = PngImage::new(ihdr, &frame.data)?;
             let (filtered, _) = image.filter_image(filter.clone(), opts.optimize_alpha);
             let max_size = Some(frame.data.len() - 1);
-            if let Ok(data) = opts.deflate.deflate(&filtered, max_size) {
+            if let Ok(data) = opts.deflater.deflate(&filtered, max_size) {
                 debug!(
                     "Recompressed fdAT #{:<2}: {} ({} bytes decrease)",
                     i,
@@ -671,7 +668,7 @@ fn copy_permissions(metadata_input: &Metadata, out_file: &File) -> PngResult<()>
         .set_permissions(metadata_input.permissions())
         .map_err(|err_io| {
             PngError::new(&format!(
-                "unable to set permissions for output file: {err_io}"
+                "Unable to set permissions for output file: {err_io}"
             ))
         })
 }
@@ -683,12 +680,11 @@ fn copy_times(_: &Metadata, _: &Path) -> PngResult<()> {
 
 #[cfg(feature = "filetime")]
 fn copy_times(input_path_meta: &Metadata, out_path: &Path) -> PngResult<()> {
-    let atime = filetime::FileTime::from_last_access_time(input_path_meta);
     let mtime = filetime::FileTime::from_last_modification_time(input_path_meta);
-    trace!("attempting to set file times: atime: {atime:?}, mtime: {mtime:?}");
-    filetime::set_file_times(out_path, atime, mtime).map_err(|err_io| {
+    trace!("attempting to set file modification time: {mtime:?}");
+    filetime::set_file_mtime(out_path, mtime).map_err(|err_io| {
         PngError::new(&format!(
-            "unable to set file times on {out_path:?}: {err_io}"
+            "Unable to set file times on {out_path:?}: {err_io}"
         ))
     })
 }
diff --git a/src/main.rs b/src/main.rs
index 17909628..f2ee9e3b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,7 +17,7 @@
 mod rayon;
 
 #[cfg(feature = "zopfli")]
-use std::num::NonZeroU8;
+use std::num::NonZeroU64;
 use std::{
     ffi::OsString, fs::DirBuilder, io::Write, path::PathBuf, process::ExitCode, time::Duration,
 };
@@ -26,7 +26,9 @@ use clap::ArgMatches;
 mod cli;
 use indexmap::IndexSet;
 use log::{Level, LevelFilter, error, warn};
-use oxipng::{Deflaters, FilterStrategy, InFile, Options, OutFile, PngError, StripChunks};
+#[cfg(feature = "zopfli")]
+use oxipng::ZopfliOptions;
+use oxipng::{Deflater, FilterStrategy, InFile, Options, OutFile, PngError, StripChunks};
 use rayon::prelude::*;
 
 use crate::cli::DISPLAY_CHUNKS;
@@ -198,7 +200,7 @@ fn parse_opts_into_struct(
     };
 
     if let Some(x) = matches.get_one::<IndexSet<u8>>("filters") {
-        opts.filter = x
+        opts.filters = x
             .iter()
             .map(|&f| match f {
                 0..=4 => FilterStrategy::Basic(f.try_into().unwrap()),
@@ -233,7 +235,7 @@ fn parse_opts_into_struct(
         None
     };
 
-    let out_file = if matches.get_flag("pretend") {
+    let out_file = if matches.get_flag("dry-run") {
         OutFile::None
     } else if matches.get_flag("stdout") {
         OutFile::StdOut
@@ -276,10 +278,10 @@ fn parse_opts_into_struct(
     opts.idat_recoding = !matches.get_flag("no-recoding");
 
     if let Some(x) = matches.get_one::<String>("interlace") {
-        opts.interlace = if x == "keep" {
-            None
-        } else {
-            x.parse::<u8>().unwrap().try_into().ok()
+        opts.interlace = match x.as_str() {
+            "off" | "0" => Some(false),
+            "on" | "1" => Some(true),
+            _ => None, // keep
         };
     }
 
@@ -335,13 +337,18 @@ fn parse_opts_into_struct(
 
     #[cfg(feature = "zopfli")]
     if matches.get_flag("zopfli") {
-        let iterations = *matches.get_one::<i64>("iterations").unwrap();
-        opts.deflate = Deflaters::Zopfli {
-            iterations: NonZeroU8::new(iterations as u8).unwrap(),
-        };
+        let iteration_count = *matches.get_one::<NonZeroU64>("iterations").unwrap();
+        let iterations_without_improvement = *matches
+            .get_one::<NonZeroU64>("iterations-without-improvement")
+            .unwrap_or(&NonZeroU64::MAX);
+        opts.deflater = Deflater::Zopfli(ZopfliOptions {
+            iteration_count,
+            iterations_without_improvement,
+            ..Default::default()
+        });
     }
-    if let (Deflaters::Libdeflater { compression }, Some(x)) =
-        (&mut opts.deflate, matches.get_one::<i64>("compression"))
+    if let (Deflater::Libdeflater { compression }, Some(x)) =
+        (&mut opts.deflater, matches.get_one::<i64>("compression"))
     {
         *compression = *x as u8;
     }
diff --git a/src/options.rs b/src/options.rs
index 48f30141..a712c5dd 100644
--- a/src/options.rs
+++ b/src/options.rs
@@ -7,9 +7,7 @@ use std::{
 use indexmap::{IndexSet, indexset};
 use log::warn;
 
-use crate::{
-    deflate::Deflaters, filters::FilterStrategy, headers::StripChunks, interlace::Interlacing,
-};
+use crate::{deflate::Deflater, filters::FilterStrategy, headers::StripChunks};
 
 /// Write destination for [`optimize`][crate::optimize].
 /// You can use [`optimize_from_memory`](crate::optimize_from_memory) to avoid external I/O.
@@ -99,16 +97,14 @@ pub struct Options {
     /// Which `FilterStrategy` to try on the file
     ///
     /// Default: `None,Sub,Entropy,Bigrams`
-    pub filter: IndexSet<FilterStrategy>,
-    /// Whether to change the interlacing type of the file.
+    pub filters: IndexSet<FilterStrategy>,
+    /// Whether to change the interlacing of the file.
     ///
-    /// These are the interlacing types avaliable:
-    /// - `None` will not change the current interlacing type.
-    /// - `Some(x)` will change the file to interlacing mode `x`.
-    ///   See [`Interlacing`] for the possible interlacing types.
+    /// - `None` will not change the current interlacing.
+    /// - `Some(x)` will turn interlacing on or off.
     ///
-    /// Default: `Some(Interlacing::None)`
-    pub interlace: Option<Interlacing>,
+    /// Default: `Some(false)`
+    pub interlace: Option<bool>,
     /// Whether to allow transparent pixels to be altered to improve compression.
     ///
     /// Default: `false`
@@ -148,7 +144,7 @@ pub struct Options {
     #[cfg_attr(feature = "zopfli", doc = "(e.g. Zopfli)")]
     ///
     /// Default: `Libdeflater`
-    pub deflate: Deflaters,
+    pub deflater: Deflater,
     /// Whether to use fast evaluation to pick the best filter
     ///
     /// Default: `true`
@@ -187,16 +183,16 @@ impl Options {
     // The following methods make assumptions that they are operating
     // on an `Options` struct generated by the `default` method.
     fn apply_preset_0(mut self) -> Self {
-        self.filter.clear();
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        self.filters.clear();
+        if let Deflater::Libdeflater { compression } = &mut self.deflater {
             *compression = 5;
         }
         self
     }
 
     fn apply_preset_1(mut self) -> Self {
-        self.filter.clear();
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        self.filters.clear();
+        if let Deflater::Libdeflater { compression } = &mut self.deflater {
             *compression = 10;
         }
         self
@@ -208,7 +204,7 @@ impl Options {
 
     fn apply_preset_3(mut self) -> Self {
         self.fast_evaluation = false;
-        self.filter = indexset! {
+        self.filters = indexset! {
             FilterStrategy::NONE,
             FilterStrategy::Bigrams,
             FilterStrategy::BigEnt,
@@ -218,7 +214,7 @@ impl Options {
     }
 
     fn apply_preset_4(mut self) -> Self {
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        if let Deflater::Libdeflater { compression } = &mut self.deflater {
             *compression = 12;
         }
         self.apply_preset_3()
@@ -226,19 +222,19 @@ impl Options {
 
     fn apply_preset_5(mut self) -> Self {
         self.fast_evaluation = false;
-        self.filter.insert(FilterStrategy::UP);
-        self.filter.insert(FilterStrategy::MinSum);
-        self.filter.insert(FilterStrategy::BigEnt);
-        self.filter.insert(FilterStrategy::Brute);
-        if let Deflaters::Libdeflater { compression } = &mut self.deflate {
+        self.filters.insert(FilterStrategy::UP);
+        self.filters.insert(FilterStrategy::MinSum);
+        self.filters.insert(FilterStrategy::BigEnt);
+        self.filters.insert(FilterStrategy::Brute);
+        if let Deflater::Libdeflater { compression } = &mut self.deflater {
             *compression = 12;
         }
         self
     }
 
     fn apply_preset_6(mut self) -> Self {
-        self.filter.insert(FilterStrategy::AVERAGE);
-        self.filter.insert(FilterStrategy::PAETH);
+        self.filters.insert(FilterStrategy::AVERAGE);
+        self.filters.insert(FilterStrategy::PAETH);
         self.apply_preset_5()
     }
 }
@@ -249,13 +245,13 @@ impl Default for Options {
         Self {
             fix_errors: false,
             force: false,
-            filter: indexset! {
+            filters: indexset! {
                 FilterStrategy::NONE,
                 FilterStrategy::SUB,
                 FilterStrategy::Entropy,
                 FilterStrategy::Bigrams
             },
-            interlace: Some(Interlacing::None),
+            interlace: Some(false),
             optimize_alpha: false,
             bit_depth_reduction: true,
             color_type_reduction: true,
@@ -264,7 +260,7 @@ impl Default for Options {
             idat_recoding: true,
             scale_16: false,
             strip: StripChunks::None,
-            deflate: Deflaters::Libdeflater { compression: 11 },
+            deflater: Deflater::Libdeflater { compression: 11 },
             fast_evaluation: true,
             timeout: None,
         }
diff --git a/src/png/mod.rs b/src/png/mod.rs
index c13c761e..e0f0acae 100644
--- a/src/png/mod.rs
+++ b/src/png/mod.rs
@@ -1,9 +1,4 @@
-use std::{
-    fs::File,
-    io::{BufReader, Read, Write},
-    path::Path,
-    sync::Arc,
-};
+use std::{fs, io::Write, path::Path, sync::Arc};
 
 use bitvec::bitarr;
 use libdeflater::{CompressionLvl, Compressor};
@@ -19,7 +14,7 @@ use crate::{
     error::PngError,
     filters::*,
     headers::*,
-    interlace::{Interlacing, deinterlace_image, interlace_image},
+    interlace::{deinterlace_image, interlace_image},
 };
 
 pub(crate) mod scan_lines;
@@ -62,28 +57,7 @@ impl PngData {
     }
 
     pub fn read_file(filepath: &Path) -> Result<Vec<u8>, PngError> {
-        let file = match File::open(filepath) {
-            Ok(f) => f,
-            Err(_) => return Err(PngError::new("Failed to open file for reading")),
-        };
-        let file_len = file.metadata().map(|m| m.len() as usize).unwrap_or(0);
-        let mut reader = BufReader::new(file);
-        // Check file for PNG header
-        let mut header = [0; 8];
-        if reader.read_exact(&mut header).is_err() {
-            return Err(PngError::new("Not a PNG file: too small"));
-        }
-        if !file_header_is_valid(&header) {
-            return Err(PngError::new("Invalid PNG header detected"));
-        }
-        // Read raw png data into memory
-        let mut byte_data: Vec<u8> = Vec::with_capacity(file_len);
-        byte_data.extend_from_slice(&header);
-        match reader.read_to_end(&mut byte_data) {
-            Ok(_) => (),
-            Err(_) => return Err(PngError::new("Failed to read from file")),
-        }
-        Ok(byte_data)
+        fs::read(filepath).map_err(|e| PngError::ReadFailed(filepath.display().to_string(), e))
     }
 
     /// Create a new `PngData` struct by reading a slice
@@ -293,18 +267,17 @@ impl PngImage {
         Ok(image)
     }
 
-    /// Convert the image to the specified interlacing type
-    /// Returns true if the interlacing was changed, false otherwise
-    /// The `interlace` parameter specifies the *new* interlacing mode
+    /// Enable or disable interlacing
+    /// Returns the new image if the interlacing was changed, None otherwise
     /// Assumes that the data has already been de-filtered
     #[inline]
     #[must_use]
-    pub fn change_interlacing(&self, interlace: Interlacing) -> Option<Self> {
+    pub fn change_interlacing(&self, interlace: bool) -> Option<Self> {
         if interlace == self.ihdr.interlaced {
             return None;
         }
 
-        Some(if interlace == Interlacing::Adam7 {
+        Some(if interlace {
             // Convert progressive to interlaced data
             interlace_image(self)
         } else {
diff --git a/src/png/scan_lines.rs b/src/png/scan_lines.rs
index e91133a5..e19bafc8 100644
--- a/src/png/scan_lines.rs
+++ b/src/png/scan_lines.rs
@@ -1,4 +1,4 @@
-use crate::{interlace::Interlacing, png::PngImage};
+use crate::png::PngImage;
 
 /// An iterator over the scan lines of a PNG image
 #[derive(Debug, Clone)]
@@ -69,7 +69,7 @@ impl ScanLineRanges {
             width: png.ihdr.width,
             height: png.ihdr.height,
             left: png.data.len(),
-            pass: if png.ihdr.interlaced == Interlacing::Adam7 {
+            pass: if png.ihdr.interlaced {
                 Some((1, 0))
             } else {
                 None
diff --git a/src/reduction/mod.rs b/src/reduction/mod.rs
index 132ae802..c8444fff 100644
--- a/src/reduction/mod.rs
+++ b/src/reduction/mod.rs
@@ -1,6 +1,6 @@
 use std::sync::Arc;
 
-use crate::{ColorType, Deadline, Deflaters, Options, evaluate::Evaluator, png::PngImage};
+use crate::{ColorType, Deadline, Deflater, Options, evaluate::Evaluator, png::PngImage};
 
 pub mod alpha;
 use crate::alpha::*;
@@ -21,8 +21,8 @@ pub(crate) fn perform_reductions(
 
     // At low compression levels, skip some transformations which are less likely to be effective
     // This currently affects optimization presets 0-2
-    let cheap = match opts.deflate {
-        Deflaters::Libdeflater { compression } => compression < 12 && opts.fast_evaluation,
+    let cheap = match opts.deflater {
+        Deflater::Libdeflater { compression } => compression < 12 && opts.fast_evaluation,
         _ => false,
     };
 
diff --git a/src/reduction/palette.rs b/src/reduction/palette.rs
index 0d07d986..dca9b643 100644
--- a/src/reduction/palette.rs
+++ b/src/reduction/palette.rs
@@ -2,7 +2,6 @@ use indexmap::IndexSet;
 use rgb::RGBA8;
 
 use crate::{
-    Interlacing,
     colors::{BitDepth, ColorType},
     headers::IhdrData,
     png::{PngImage, scan_lines::ScanLine},
@@ -134,7 +133,7 @@ pub fn sorted_palette(png: &PngImage) -> Option<PngImage> {
 #[must_use]
 pub fn sorted_palette_mzeng(png: &PngImage) -> Option<PngImage> {
     // Interlacing not currently supported
-    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced != Interlacing::None {
+    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced {
         return None;
     }
     let palette = match &png.ihdr.color_type {
@@ -156,7 +155,7 @@ pub fn sorted_palette_mzeng(png: &PngImage) -> Option<PngImage> {
 #[must_use]
 pub fn sorted_palette_battiato(png: &PngImage) -> Option<PngImage> {
     // Interlacing not currently supported
-    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced != Interlacing::None {
+    if png.ihdr.bit_depth != BitDepth::Eight || png.ihdr.interlaced {
         return None;
     }
     let palette = match &png.ihdr.color_type {
diff --git a/tests/filters.rs b/tests/filters.rs
index 3d696360..4f6f0025 100644
--- a/tests/filters.rs
+++ b/tests/filters.rs
@@ -14,7 +14,6 @@ const RGBA: u8 = 6;
 fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
     let options = oxipng::Options {
         force: true,
-        filter: indexset! {FilterStrategy::NONE},
         ..Default::default()
     };
     (OutFile::from_path(input.with_extension("out.png")), options)
@@ -32,8 +31,7 @@ fn test_it_converts(
 
     let (output, mut opts) = get_opts(&input);
     let png = PngData::new(&input, &opts).unwrap();
-    opts.filter = IndexSet::new();
-    opts.filter.insert(filter);
+    opts.filters = indexset! {filter};
     assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
     assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in);
 
diff --git a/tests/flags.rs b/tests/flags.rs
index 4baa619b..de6afbde 100644
--- a/tests/flags.rs
+++ b/tests/flags.rs
@@ -1,5 +1,3 @@
-#[cfg(feature = "zopfli")]
-use std::num::NonZeroU8;
 use std::{
     fs::remove_file,
     path::{Path, PathBuf},
@@ -16,7 +14,7 @@ fn get_opts(input: &Path) -> (OutFile, Options) {
     let options = Options {
         force: true,
         fast_evaluation: false,
-        filter: indexset! {FilterStrategy::NONE},
+        filters: indexset! {FilterStrategy::NONE},
         ..Default::default()
     };
     (OutFile::from_path(input.with_extension("out.png")), options)
@@ -316,7 +314,7 @@ fn strip_chunks_none() {
 fn interlacing_0_to_1() {
     let input = PathBuf::from("tests/files/interlacing_0_to_1.png");
     let (output, mut opts) = get_opts(&input);
-    opts.interlace = Some(Interlacing::Adam7);
+    opts.interlace = Some(true);
 
     test_it_converts_callbacks(
         input,
@@ -327,10 +325,10 @@ fn interlacing_0_to_1() {
         RGB,
         BitDepth::Eight,
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::None);
+            assert!(!png.raw.ihdr.interlaced);
         },
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::Adam7);
+            assert!(png.raw.ihdr.interlaced);
         },
     );
 }
@@ -339,7 +337,7 @@ fn interlacing_0_to_1() {
 fn interlacing_1_to_0() {
     let input = PathBuf::from("tests/files/interlacing_1_to_0.png");
     let (output, mut opts) = get_opts(&input);
-    opts.interlace = Some(Interlacing::None);
+    opts.interlace = Some(false);
 
     test_it_converts_callbacks(
         input,
@@ -350,10 +348,10 @@ fn interlacing_1_to_0() {
         RGB,
         BitDepth::Eight,
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::Adam7);
+            assert!(png.raw.ihdr.interlaced);
         },
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::None);
+            assert!(!png.raw.ihdr.interlaced);
         },
     );
 }
@@ -362,7 +360,7 @@ fn interlacing_1_to_0() {
 fn interlacing_0_to_1_small_files() {
     let input = PathBuf::from("tests/files/interlacing_0_to_1_small_files.png");
     let (output, mut opts) = get_opts(&input);
-    opts.interlace = Some(Interlacing::Adam7);
+    opts.interlace = Some(true);
 
     test_it_converts_callbacks(
         input,
@@ -373,10 +371,10 @@ fn interlacing_0_to_1_small_files() {
         RGB,
         BitDepth::Eight,
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::None);
+            assert!(!png.raw.ihdr.interlaced);
         },
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::Adam7);
+            assert!(png.raw.ihdr.interlaced);
         },
     );
 }
@@ -385,7 +383,7 @@ fn interlacing_0_to_1_small_files() {
 fn interlacing_1_to_0_small_files() {
     let input = PathBuf::from("tests/files/interlacing_1_to_0_small_files.png");
     let (output, mut opts) = get_opts(&input);
-    opts.interlace = Some(Interlacing::None);
+    opts.interlace = Some(false);
 
     test_it_converts_callbacks(
         input,
@@ -396,10 +394,10 @@ fn interlacing_1_to_0_small_files() {
         RGB,
         BitDepth::Eight,
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::Adam7);
+            assert!(png.raw.ihdr.interlaced);
         },
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::None);
+            assert!(!png.raw.ihdr.interlaced);
         },
     );
 }
@@ -408,8 +406,8 @@ fn interlacing_1_to_0_small_files() {
 fn interlaced_0_to_1_other_filter_mode() {
     let input = PathBuf::from("tests/files/interlaced_0_to_1_other_filter_mode.png");
     let (output, mut opts) = get_opts(&input);
-    opts.interlace = Some(Interlacing::Adam7);
-    opts.filter = indexset! {FilterStrategy::PAETH};
+    opts.interlace = Some(true);
+    opts.filters = indexset! {FilterStrategy::PAETH};
 
     test_it_converts_callbacks(
         input,
@@ -420,10 +418,10 @@ fn interlaced_0_to_1_other_filter_mode() {
         GRAY,
         BitDepth::Sixteen,
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::None);
+            assert!(!png.raw.ihdr.interlaced);
         },
         |png| {
-            assert_eq!(png.raw.ihdr.interlaced, Interlacing::Adam7);
+            assert!(png.raw.ihdr.interlaced);
         },
     );
 }
@@ -437,8 +435,6 @@ fn preserve_attrs() {
         .metadata()
         .expect("unable to get file metadata for output file");
     #[cfg(feature = "filetime")]
-    let atime_canon = filetime::FileTime::from_last_access_time(&meta_input);
-    #[cfg(feature = "filetime")]
     let mtime_canon = filetime::FileTime::from_last_modification_time(&meta_input);
 
     let (mut output, opts) = get_opts(&input);
@@ -458,12 +454,6 @@ fn preserve_attrs() {
         .metadata()
         .expect("unable to get file metadata for output file");
     #[cfg(feature = "filetime")]
-    assert_eq!(
-        &atime_canon,
-        &filetime::FileTime::from_last_access_time(&meta_output),
-        "expected access time to be identical to that of input",
-    );
-    #[cfg(feature = "filetime")]
     assert_eq!(
         &mtime_canon,
         &filetime::FileTime::from_last_modification_time(&meta_output),
@@ -649,9 +639,7 @@ fn scale_16() {
 fn zopfli_mode() {
     let input = PathBuf::from("tests/files/zopfli_mode.png");
     let (output, mut opts) = get_opts(&input);
-    opts.deflate = Deflaters::Zopfli {
-        iterations: NonZeroU8::new(15).unwrap(),
-    };
+    opts.deflater = Deflater::Zopfli(ZopfliOptions::default());
 
     test_it_converts(
         input,
diff --git a/tests/interlaced.rs b/tests/interlaced.rs
index b9007d9b..9fac6038 100644
--- a/tests/interlaced.rs
+++ b/tests/interlaced.rs
@@ -15,7 +15,7 @@ fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
     let options = oxipng::Options {
         force: true,
         fast_evaluation: false,
-        filter: indexset! {FilterStrategy::NONE},
+        filters: indexset! {FilterStrategy::NONE},
         interlace: None,
         ..Default::default()
     };
@@ -35,7 +35,7 @@ fn test_it_converts(
 
     assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
     assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in);
-    assert_eq!(png.raw.ihdr.interlaced, Interlacing::Adam7);
+    assert!(png.raw.ihdr.interlaced);
 
     match oxipng::optimize(&InFile::Path(input), &output, &opts) {
         Ok(_) => (),
diff --git a/tests/interlacing.rs b/tests/interlacing.rs
index ea7fd5a9..83bfcd7f 100644
--- a/tests/interlacing.rs
+++ b/tests/interlacing.rs
@@ -11,7 +11,7 @@ const INDEXED: u8 = 3;
 fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
     let options = oxipng::Options {
         force: true,
-        filter: indexset! {FilterStrategy::NONE},
+        filters: indexset! {FilterStrategy::NONE},
         ..Default::default()
     };
     (OutFile::from_path(input.with_extension("out.png")), options)
@@ -19,7 +19,7 @@ fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
 
 fn test_it_converts(
     input: &str,
-    interlace: Interlacing,
+    interlace: bool,
     color_type_in: u8,
     bit_depth_in: BitDepth,
     color_type_out: u8,
@@ -31,14 +31,7 @@ fn test_it_converts(
     opts.interlace = Some(interlace);
     assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
     assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in);
-    assert_eq!(
-        png.raw.ihdr.interlaced,
-        if interlace == Interlacing::Adam7 {
-            Interlacing::None
-        } else {
-            Interlacing::Adam7
-        }
-    );
+    assert_eq!(png.raw.ihdr.interlaced, !interlace);
 
     match oxipng::optimize(&InFile::Path(input), &output, &opts) {
         Ok(_) => (),
@@ -65,7 +58,7 @@ fn test_it_converts(
 fn deinterlace_rgb_16() {
     test_it_converts(
         "tests/files/interlaced_rgb_16_should_be_rgb_16.png",
-        Interlacing::None,
+        false,
         RGB,
         BitDepth::Sixteen,
         RGB,
@@ -77,7 +70,7 @@ fn deinterlace_rgb_16() {
 fn deinterlace_rgb_8() {
     test_it_converts(
         "tests/files/interlaced_rgb_8_should_be_rgb_8.png",
-        Interlacing::None,
+        false,
         RGB,
         BitDepth::Eight,
         RGB,
@@ -89,7 +82,7 @@ fn deinterlace_rgb_8() {
 fn deinterlace_palette_8() {
     test_it_converts(
         "tests/files/interlaced_palette_8_should_be_palette_8.png",
-        Interlacing::None,
+        false,
         INDEXED,
         BitDepth::Eight,
         INDEXED,
@@ -101,7 +94,7 @@ fn deinterlace_palette_8() {
 fn deinterlace_palette_4() {
     test_it_converts(
         "tests/files/interlaced_palette_4_should_be_palette_4.png",
-        Interlacing::None,
+        false,
         INDEXED,
         BitDepth::Four,
         INDEXED,
@@ -113,7 +106,7 @@ fn deinterlace_palette_4() {
 fn deinterlace_palette_2() {
     test_it_converts(
         "tests/files/interlaced_palette_2_should_be_palette_2.png",
-        Interlacing::None,
+        false,
         INDEXED,
         BitDepth::Two,
         INDEXED,
@@ -125,7 +118,7 @@ fn deinterlace_palette_2() {
 fn deinterlace_palette_1() {
     test_it_converts(
         "tests/files/interlaced_palette_1_should_be_palette_1.png",
-        Interlacing::None,
+        false,
         INDEXED,
         BitDepth::One,
         INDEXED,
@@ -137,7 +130,7 @@ fn deinterlace_palette_1() {
 fn interlace_rgb_16() {
     test_it_converts(
         "tests/files/rgb_16_should_be_rgb_16.png",
-        Interlacing::Adam7,
+        true,
         RGB,
         BitDepth::Sixteen,
         RGB,
@@ -149,7 +142,7 @@ fn interlace_rgb_16() {
 fn interlace_rgb_8() {
     test_it_converts(
         "tests/files/rgb_8_should_be_rgb_8.png",
-        Interlacing::Adam7,
+        true,
         RGB,
         BitDepth::Eight,
         RGB,
@@ -161,7 +154,7 @@ fn interlace_rgb_8() {
 fn interlace_palette_8() {
     test_it_converts(
         "tests/files/palette_8_should_be_palette_8.png",
-        Interlacing::Adam7,
+        true,
         INDEXED,
         BitDepth::Eight,
         INDEXED,
@@ -173,7 +166,7 @@ fn interlace_palette_8() {
 fn interlace_palette_4() {
     test_it_converts(
         "tests/files/palette_4_should_be_palette_4.png",
-        Interlacing::Adam7,
+        true,
         INDEXED,
         BitDepth::Four,
         INDEXED,
@@ -185,7 +178,7 @@ fn interlace_palette_4() {
 fn interlace_palette_2() {
     test_it_converts(
         "tests/files/palette_2_should_be_palette_2.png",
-        Interlacing::Adam7,
+        true,
         INDEXED,
         BitDepth::Two,
         INDEXED,
@@ -197,7 +190,7 @@ fn interlace_palette_2() {
 fn interlace_palette_1() {
     test_it_converts(
         "tests/files/palette_1_should_be_palette_1.png",
-        Interlacing::Adam7,
+        true,
         INDEXED,
         BitDepth::One,
         INDEXED,
diff --git a/tests/raw.rs b/tests/raw.rs
index d50a58e1..155f415a 100644
--- a/tests/raw.rs
+++ b/tests/raw.rs
@@ -5,7 +5,7 @@ use oxipng::{internal_tests::*, *};
 fn get_opts() -> Options {
     Options {
         force: true,
-        filter: indexset! {FilterStrategy::NONE},
+        filters: indexset! {FilterStrategy::NONE},
         ..Default::default()
     }
 }
diff --git a/tests/reduction.rs b/tests/reduction.rs
index 6ba3236d..bd362dda 100644
--- a/tests/reduction.rs
+++ b/tests/reduction.rs
@@ -15,7 +15,7 @@ fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
     let options = oxipng::Options {
         force: true,
         fast_evaluation: false,
-        filter: indexset! {FilterStrategy::NONE},
+        filters: indexset! {FilterStrategy::NONE},
         ..Default::default()
     };
     (OutFile::from_path(input.with_extension("out.png")), options)
@@ -36,7 +36,7 @@ fn test_it_converts(
 
     assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
     assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in, "test file is broken");
-    assert_eq!(png.raw.ihdr.interlaced, Interlacing::None);
+    assert!(!png.raw.ihdr.interlaced);
 
     match oxipng::optimize(&InFile::Path(input), &output, &opts) {
         Ok(_) => (),
diff --git a/tests/regression.rs b/tests/regression.rs
index 89756c29..16b0992e 100644
--- a/tests/regression.rs
+++ b/tests/regression.rs
@@ -14,7 +14,7 @@ const RGBA: u8 = 6;
 fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
     let options = oxipng::Options {
         force: true,
-        filter: indexset! {FilterStrategy::NONE},
+        filters: indexset! {FilterStrategy::NONE},
         ..Default::default()
     };
     (OutFile::from_path(input.with_extension("out.png")), options)
@@ -75,7 +75,7 @@ fn test_it_converts(
 fn issue_42() {
     let input = "tests/files/issue-42.png";
     let (output, mut opts) = get_opts(Path::new(input));
-    opts.interlace = Some(Interlacing::Adam7);
+    opts.interlace = Some(true);
     test_it_converts(
         input,
         Some((output, opts)),
@@ -186,7 +186,7 @@ fn issue_175() {
 fn issue_182() {
     let input = "tests/files/issue-182.png";
     let (output, mut opts) = get_opts(Path::new(input));
-    opts.interlace = Some(Interlacing::Adam7);
+    opts.interlace = Some(true);
 
     test_it_converts(
         input,
diff --git a/tests/strategies.rs b/tests/strategies.rs
index 264e6983..de4db2c3 100644
--- a/tests/strategies.rs
+++ b/tests/strategies.rs
@@ -30,7 +30,7 @@ fn test_it_converts(
 
     let (output, mut opts) = get_opts(&input);
     let png = PngData::new(&input, &opts).unwrap();
-    opts.filter = indexset! {filter};
+    opts.filters = indexset! {filter};
     assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
     assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in);