I am a tad confused here. Are you saying that the images vanished once you turned off the phone? or that you just can't find them?
If they were 'deleted' then it is possible that you won't be able to get them back. Once gone, then really aren't meant to be restored on a phone. However the following info 'may' help.
There are a few apps/programs out there that 'may' be able to help you recover the data.
A few of the programs you could try would be... DiskDigger, MobiSaver, Android-Recovery and Tenorshare. They are all data recovery apps/programs. There are many others out there, so check around and see which you would rather try. There is also one called RECUVA, that I have heard is free, which you could try.
One important note...