This has been done before, in many variations. There's always a way for the recipient to save a copy. At least this scheme doesn't require special client softwa

This has been done before, in many variations. There's always a way for the recipient to save a copy. At least this scheme doesn't require special client software. Note that this depends on the recipient's email client making a request for the image, which, thankfully, most clients provide a way to turn off.