Stripping of Gamma and color gamut shouldn't happen

[sgoehler]

Hello,

first, thanks for this great project, it's really useful to me!

One thing that really shouldn't happen is the removal of gamut and gamma information. I know I can turn off stripping additional PNG data, but that will turn off every stripping of additional information.
The issue is that the gamut is essential to the correct displayment of an image. If the gamut is wrong, the colors will be wrong, if display or image differ. Example: a DisplayP3 image is reduced. Now, without gamut information, the image will be shown incorrectly on sRGB screens. On a DisplayP3 screen on the other hand it depends on the decoder, but it's probably safe to assume that it will assume sRGB - which will, again, result in wrong colors.

Gamut and Gamma information is essential to an image, if it exists. It may be safe to remove if the input image is in sRGB color space, but it will result in incorrect colors in any other case.