Some changes in libpng 1.6+ cause it issue warning or even not work correctly with the original HP/MS sRGB profile. You'll notice this in stderr:
libpng warning: iCCP: known incorrect sRGB profile
The old profile uses a D50 whitepoint, where D65 is standard. This profile is not uncommon, being used by Adobe Photoshop, although it was not embedded into images by default.
The simplest solution is simply to remove the embedded profile from your image. This can cause a slight shift in color *IF* have have a properly calibrated system, monitor, and software. If you really need it (say for a print shop), you can alternatively embed a different color profile. If this applies to you, you probably have the profiles you need already.
- To remove the embedded profile, go to
Image > Mode > Assign Color Profileand set it to
RGB workspace(sRGB built-in)
- To change the embedded profile, go to
Image > Mode > Convert to Color Profilewhere you can choose a profile you already have loaded or load a new one from disk.
- To remove the embedded profile, just run
% convert -strip <input filename> <output filename>