The background of currently loading images is always black. This is kind of distracting. It should be transparent, or at least similar to the background of the page.
This can be fixed by returning true in all cases in ImageSource::frameHasAlphaAtIndex() in ImageSourceCairo.cpp.
A better fix would preserve the optimization. I'm working on a solution now.
Created attachment 17573 [details]
Includes a workaround for http://bugs.webkit.org/show_bug.cgi?id=16169
Created attachment 17574 [details]
Comment on attachment 17574 [details]
Landed in r28109.