this also happened to me yesterday when i deleted the last photo from my iphone album. the 10-15 pictures before it suddenly turned black in camera roll. meanwhile, the rest are visible (>500 pics). i shifted back and forth to camera roll-albums-view, turned the iphone on and off, took another pic, deleted another, but nothing restored the photos. like the others who posted here, when i selected the blackened😕 photos, you can view them individually. yes, this was after i updated to 4.0.2. clearly a programming bug 😡