Point to bear in mind for digicam owners
The original file from the camera usually contains a lot of details about the time, date, camera, exposure etc. I find this a useful feature of the camera JPEG format (exif or summat like that)
Once you edit the file in something like Photoshop or Paint Shop Pro and save it back to the original location, these details are lost from within the file.
I always keep my original photos in a specific folder which is archived to CDRs and also to a large external USB hard disk (keeps them easy to access). If I work on the photos, I move them to another place, especially if making significant changes, although I have been caught out on occasion and altered the orignal irreversibly.
Back up often. There's nothing like a hard disk failure to bring home the fragility of digital photos. Don't ask me how I know...!
Mark.