Are the photos being kept on the phone or on a SD card? I ask because I have not run into this error happening on files kept on a phone's internal storage, but I have when kept on a SD card. It usually occurs when the card is the wrong type for the device, or the card is having trouble.
The only fixes I know of would be to move the files to a computer and use a photo recovery software (there are a few out there) to try and recover the images.
If this is happening on the phone itself, then I would still suggest the above for getting the photos back, but I would also start to wonder what is wrong with the phone. Perhaps a virus or malware that is causing the issue? That I can't say for certain, but is not something, again, I have seen happen with the phone's storage before, only on cards.