So, look at the OP's avatar in this thread. Is it gross and nasty looking? Then you probably upgraded to the new version of firefox. Which, for some reason, is convinced that .png images should all look darker than they are.
I found this nifty little add on called Color Management that fixes the problem nicely. I'm sure it'll make some fancy-pants photo-shop using folks' stuff look a little different than it should, but...meh.
