Fix determing grayscale for 1-color palettes

imageio · Mar 12, 2018 · a22145a · a22145a
1 parent 309a080
commit a22145a
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/imageio/plugins/pillow.py b/imageio/plugins/pillow.py
@@ -507,7 +507,7 @@ def _palette_is_grayscale(pil_image):
     palette = np.asarray(pil_image.getpalette()).reshape((256, 3))
     # Not all palette colors are used; unused colors have junk values.
     start, stop = pil_image.getextrema()
-    valid_palette = palette[start:stop]
+    valid_palette = palette[start:stop+1]
     # Image is grayscale if channel differences (R - G and G - B)
     # are all zero.
     return np.allclose(np.diff(valid_palette), 0)