From bug #45008: [marlon bishop] For PNG - there's a problem with Mozilla's gamma correction algorithm too, in addition to the trns problem. Then the fact that CSS specified colors are not gamma corrected which precludes us from using PNG in a skin. You can never match colors properly without the same gamma correction everywhere. From the CSS 2 rec.: "Conforming user agents may limit their color-displaying efforts to performing a gamma-correction on them. sRGB specifies a display gamma of 2.2 under specified viewing conditions. User agents should adjust the colors given in CSS such that, in combination with an output device's "natural" display gamma, an effective display gamma of 2.2 is produced. See the section on gamma correction for further details. Note that only colors specified in CSS are affected; e.g., images are expected to carry their own color information." "For information about gamma issues, please consult the the Gamma Tutorial in the PNG specification ([PNG10])."

*** This bug has been marked as a duplicate of 53597 ***

vrfy dupl; please search more thoroughly next time you file a bug! :-)