Google Play Store: You need fix your high-res icon. It is not a valid image

Question

This is the error message I get when attempting to give my app an image on the play store. Here is the image.

It was created in GIMP. Please help, this is keeping me from getting my app up.

Answer 1

As described on Google Play Store developer console, icon image should be:
512 x 512, 32-bit PNG (with alpha)

Your picture is (I checked with "file" Linux command)
PNG image data, 512 x 512, 8-bit colormap, non-interlaced

This happened because your image uses only a few colors and gimp decided to use png format with indexed colors so image file is as small as possible.

Answer 2

Resolved by re-saving with Paint.NET. I guess it's some kind of GIMP bug.