Safari PNG Rendering

I just spent quite a while trying to isolate a messed up bug in Safari where png images are returned slightly darker. This came up when I overlayed two backgrounds both of which were had 100% opacity. All browsers on windows rendered everything properly (Firefox, IE6, IE7, and Opera), but Safari on the other hand did not. In the end I just resaved the background as a gif and this fixed the problem. Damn browser bugs! :@