You can just change the photo filename name if you wish, the filename and not the actual photo.
I just don't know why you would want to do that.
When a photo is uploaded, it puts the photo(s) into a directory somewhere and
the photo filename is written into your database table? I assume that is what you're doing.
So your column name "photo" is the filename of the photo itself.
Is that how you have it set up?