For the photo hub, there is no way to hide or lock pictures (less pin locking your phone).... However, most of those photo lock apps do work well, the catch is, once the photo(s) have been added to the locked app, you have to manually delete the photos from the photo hub. The lock apps will store the photos in their own app folder... One thing to make sure on, is that the photo lock app can export said photos back to your photo hub and/or make sure they are backed up somewhere, because they won't necessarily be backed up if your phone dies/gets traded in.