I have been having the pictures disappear from my default gallery app as well (Droid Incredible with HTC sense with Android 2.3.4). I can restart and have my pictures back for about a day before they are missing again. I can find them on Astro if they're not in gallery. I installed quickpic and they're all showing up fine (while still missing in gallery)!
I would also suggest using a cloud backup such as dropbox, google's drive or box that can be set to backup pictures as you take them, only when you are on wifi or only manually. This way even if your phone takes a dive you'll have most if not all pictures already backed up.
I would also suggest using a cloud backup such as dropbox, google's drive or box that can be set to backup pictures as you take them, only when you are on wifi or only manually. This way even if your phone takes a dive you'll have most if not all pictures already backed up.
