I had an issue similar that but with the videos and had a couple corrupt pictures that froze the pictures. What I did was hooked the iphone to the computer and copied the pics into a folder and then the offending picture was not copied and I go an error message while in process. What I ended up doing was basically backing up, then made sure that I copied all the good one to a file on the PC and had to delete the offending picture. But if you do not have Albums set and synched then this would be a good time to start and this way you can manage the pictures from your PC based on the albums. By the way hard reboot, and restart did not help me at all. Since I did the delete this never happened again.