diff --git a/src/lib.rs b/src/lib.rs
index 38c872ed..6882f00a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -687,8 +687,15 @@ fn optimize_png(png: &mut PngData, original_data: &[u8], opts: &Options) -> PngR
         }
     }
 
-    let old_png = image::load_from_memory_with_format(original_data, ImageFormat::PNG);
-    let new_png = image::load_from_memory_with_format(&output, ImageFormat::PNG);
+    let (old_png, new_png) = {
+        let old_png = || image::load_from_memory_with_format(original_data, ImageFormat::PNG);
+        let new_png = || image::load_from_memory_with_format(&output, ImageFormat::PNG);
+        #[cfg(feature = "parallel")]
+        let res = rayon::join(old_png, new_png);
+        #[cfg(not(feature = "parallel"))]
+        let res = (old_png(), new_png());
+        res
+    };
 
     if let Ok(new_png) = new_png {
         if let Ok(old_png) = old_png {
@@ -898,11 +905,15 @@ fn copy_permissions(input_path: &Path, out_file: &File, verbosity: Option<u8>) {
 fn images_equal(old_png: &DynamicImage, new_png: &DynamicImage) -> bool {
     let a = old_png
         .pixels()
-        .map(|x| x.2.channels().to_owned())
-        .filter(|p| !(p.len() == 4 && p[3] == 0));
+        .filter(|x| {
+            let p = x.2.channels();
+            !(p.len() == 4 && p[3] == 0)
+        });
     let b = new_png
         .pixels()
-        .map(|x| x.2.channels().to_owned())
-        .filter(|p| !(p.len() == 4 && p[3] == 0));
+        .filter(|x| {
+            let p = x.2.channels();
+            !(p.len() == 4 && p[3] == 0)
+        });
     a.eq(b)
 }