There is one issue I encountered is some jpeg images being shown too dark and with the contrast too high like this:
This is due to the new color profiles support being enabled by default while there is still a bug in the implementation. to work around the issue change the gfx.color_management.mode config option from the default of 2 to 0. This will get images back looking the way they do in other browsers and previous versions of Firefox. If you don’t know how to change advanced options in Firefox see the instructions here.
Once they’ve fixed the bug I’m hoping the color profile support will work OK but, there is a caveat listed at the Gfx.color_management.enabled page.
Without a properly calibrated monitor and a correct color profile, color management may actually make colors look worse.
I’m keeping my fingers crossed but, I really don’t know how well calibrated most monitors are or if they have a proper color profile installed. Hopefully I won’t need to edit all the photos in my album to make it work correctly. If it comes down to that I think Ill just add a note saying “To see the photos properly you can’t use Firefox 3.5, every other browser, including older versions of Firefox, work fine”, ouch.
More info and opinions: