I think this may be a gameplay bug. As I've had something similar happen in my game = all photos from the photobooth/greeting cards went blank and they're not fixable.
I tried clearing my game cache files and that didn't help, Sims 3 factory reset, Nraas debug enabler, resetting the town using Nraas MasterController and tried a backup as well. Nothing worked. Tried to search on the problem, but wasn't able to find much info on it other than it's a gameplay bug, and there isn't any way to fix it.