I was trying to submit an app to the Windows Phone app store. Here all pixels need to be white (#FFFFFF) or transparant (#FF####).
I had a black logo on a white background. To make the background transparant and the foreground white I used Gimp. First I made the background transparant using the magic wand and changing color to alpha. Then I inverted the remaining colors. Unfortunately the images did not get accepted in the Windows Phone app store because not all pixels were white or transparant.
How can non-white or transparant pixels in Gimp be converted to white?