My pictures taken with the flash on my 4S suck. They are really washed. I've tried it with and without the case, same result. It probably has nothing to do with the actual phone, but right before the camera actually takes the picture and the flash lights up for a second, on the screen that looks great. But when it actually snaps the photo it looks bad. Not a huge deal, but kinda annoying.
Ha, well apparently posting on this thread was just what the doctor ordered. I took a few pics in low light to test it out and show examples. And wouldn't you know it, they look great.