Blackberry Storm 953: BBthumbs.dat?

I know what these files are - essentially the same as on PC. I can delete them however, they periodically reappear. Is there anyway to keep them from coming back? I know what you're thinking "just live with them. The problem is I basically use it as a compact external harddrive - beats the hell out of a flash drive, it has 6GB space, and also allows phone calls, and full web browsing (where flash is not involved. So basically its pretty perfect - except that the dat files combined start using up to mich space.