So, for example, several of the album covers here are discolored:

If I click on the thumbnail, though, the art is correctly colored:

Redownloading the cover art from a different source still leaves the thumbnail discolored even with browser cache disabled. It happens in every browser I've tried it with and in all mobile clients (play:Sub, iSub).
It seems to affect albums at random though once they become discolored they don't change back.
I've searched around but found no references to this problem. Anyone know what might be causing it or how to fix it?