diff --git a/tests/CREDITS.md b/tests/CREDITS.md
index 454ce0e..05ea614 100644
--- a/tests/CREDITS.md
+++ b/tests/CREDITS.md
@@ -26,6 +26,13 @@ random2.webp:
 convert -delay 15 -size 99x87 xc: xc: xc: xc: +noise Random -define webp:lossless=false random_lossy.webp
 ```
 
+## images/regression
+
+color_index.webp:
+```
+convert -size 100x60 xc:skyblue -fill white -stroke black -draw "rectangle 20,10 80,50" -define webp:lossless=true color_index.webp
+```
+
 # Reference images
 
 These files are all PNGs with contents that should exactly match the associated WebP file in the _images_ directory.
@@ -47,3 +54,10 @@ random-lossy-N.png:
 ```
 for i in {1..4}; do webpmux -get frame ${i} ../../images/animated/random_lossy.webp -o random_lossy-${i}.png && dwebp random_lossy-${i}.png -nofancy -o random_lossy-${i}.png; done
 ```
+
+## Regression
+
+color_index.png:
+```
+dwebp ../../images/regression/color_index.webp -o color_index.png
+```
\ No newline at end of file
diff --git a/tests/decode.rs b/tests/decode.rs
index 38790e3..46d18e1 100644
--- a/tests/decode.rs
+++ b/tests/decode.rs
@@ -127,3 +127,4 @@ reftest!(gallery1, 1, 2, 3, 4, 5);
 reftest!(gallery2, 1_webp_ll, 2_webp_ll, 3_webp_ll, 4_webp_ll, 5_webp_ll);
 reftest!(gallery2, 1_webp_a, 2_webp_a, 3_webp_a, 4_webp_a, 5_webp_a);
 reftest!(animated, random_lossless, random_lossy);
+reftest!(regression, color_index);
diff --git a/tests/images/regression/color_index.webp b/tests/images/regression/color_index.webp
new file mode 100644
index 0000000..2493d3e
Binary files /dev/null and b/tests/images/regression/color_index.webp differ
diff --git a/tests/reference/regression/color_index.png b/tests/reference/regression/color_index.png
new file mode 100644
index 0000000..75da94d
Binary files /dev/null and b/tests/reference/regression/color_index.png differ