diff --git a/src/headers.rs b/src/headers.rs
index f57de8c7..75a814f3 100644
--- a/src/headers.rs
+++ b/src/headers.rs
@@ -44,9 +44,7 @@ impl IhdrData {
             (w * bpp).div_ceil(8) * h
         }
 
-        if !self.interlaced {
-            bitmap_size(bpp, w, h) + h
-        } else {
+        if self.interlaced {
             let mut size = bitmap_size(bpp, (w + 7) >> 3, (h + 7) >> 3) + ((h + 7) >> 3);
             if w > 4 {
                 size += bitmap_size(bpp, (w + 3) >> 3, (h + 7) >> 3) + ((h + 7) >> 3);
@@ -60,6 +58,8 @@ impl IhdrData {
                 size += bitmap_size(bpp, w >> 1, (h + 1) >> 1) + ((h + 1) >> 1);
             }
             size + bitmap_size(bpp, w, h >> 1) + (h >> 1)
+        } else {
+            bitmap_size(bpp, w, h) + h
         }
     }
 }
diff --git a/src/reduction/color.rs b/src/reduction/color.rs
index 0d1dde81..2836e656 100644
--- a/src/reduction/color.rs
+++ b/src/reduction/color.rs
@@ -54,10 +54,10 @@ pub fn reduced_to_indexed(png: &PngImage, allow_grayscale: bool) -> Option<PngIm
             let transparency_pixel = transparent_shade.map(|t| Gray::from(t as u8));
             pmap.into_iter()
                 .map(|px| {
-                    RGB::from(px).with_alpha(if Some(px) != transparency_pixel {
-                        255
-                    } else {
+                    RGB::from(px).with_alpha(if Some(px) == transparency_pixel {
                         0
+                    } else {
+                        255
                     })
                 })
                 .collect()
@@ -68,10 +68,10 @@ pub fn reduced_to_indexed(png: &PngImage, allow_grayscale: bool) -> Option<PngIm
             let transparency_pixel = transparent_color.map(|t| t.map(|c| c as u8));
             pmap.into_iter()
                 .map(|px| {
-                    px.with_alpha(if Some(px) != transparency_pixel {
-                        255
-                    } else {
+                    px.with_alpha(if Some(px) == transparency_pixel {
                         0
+                    } else {
+                        255
                     })
                 })
                 .collect()