diff --git a/tests/files/grayscale_8_should_be_palette_4.png b/tests/files/grayscale_8_should_be_palette_4.png
index 66138edb..2edd6dbf 100644
Binary files a/tests/files/grayscale_8_should_be_palette_4.png and b/tests/files/grayscale_8_should_be_palette_4.png differ
diff --git a/tests/flags.rs b/tests/flags.rs
index 2df4ea0b..5d3bdc2f 100644
--- a/tests/flags.rs
+++ b/tests/flags.rs
@@ -11,7 +11,6 @@ use std::ops::Deref;
 use std::path::Path;
 use std::path::PathBuf;
 
-const GRAYSCALE: u8 = 0;
 const RGB: u8 = 2;
 const INDEXED: u8 = 3;
 const RGBA: u8 = 6;
@@ -597,7 +596,7 @@ fn fix_errors() {
         }
     };
 
-    assert_eq!(png.raw.ihdr.color_type.png_header_code(), GRAYSCALE);
+    assert_eq!(png.raw.ihdr.color_type.png_header_code(), INDEXED);
     assert_eq!(png.raw.ihdr.bit_depth, BitDepth::Eight);
 
     // Cannot check if pixels are equal because image crate cannot read corrupt (input) PNGs
diff --git a/tests/regression.rs b/tests/regression.rs
index 9382f27a..99a9938b 100644
--- a/tests/regression.rs
+++ b/tests/regression.rs
@@ -177,8 +177,8 @@ fn issue_52_05() {
         None,
         RGBA,
         BitDepth::Eight,
-        INDEXED,
-        BitDepth::One,
+        RGB,
+        BitDepth::Eight,
     );
 }