[Threads merged]
If you don't answer our questions, we can't answer yours. So "Were these photos you took with the camera app, or did you download them from somewhere else?"
And please register, so that you don't start yet another thread that someone has to clean up.
(Gallery isn't a place, there are no pictures in it. Either you have to restart the phone (like if you moved the pictures), or the pictures got deleted somehow.)