Once the photo gets onto your hard drive it is almost impossible to erase by any means except a full wipe of the drive,. I'm not an expert, but I've been told that almost anyone who knows the rudiments of information recovery can with the proper programs access every photo that has ever been saved on a computer's hard drive. The type of entities which have the requisite hardware and software to do the job include sophisticated metropolitan police departments, many private investigation agencies, almost every computer repair shop, and lots of internet hackers.
