Images can't contain alpha channels or transparencies

Question

Apple has released new version of iTunes Connect & I got an error message when I tried to set Screenshots on itunes connect for my app.

\"Images can\'t c         


        

Answer 1

You can remove the alpha channel from a PNG file from the command line with pngcrush, using the flag "-c 2":

$ file input.png
input.png: PNG image data, 1024 x 1024, 8-bit/color RGBA, non-interlaced
$ pngcrush -q -c 2 input.png output.png
libpng warning: iCCP: known incorrect sRGB profile
$ file output.png
output.png: PNG image data, 1024 x 1024, 8-bit/color RGB, non-interlaced

Note the change from RGBA to RGB: the Alpha channel is gone!

pngcrush lives at http://pmt.sourceforge.net/pngcrush/