I realize that a JPEG is a compressed file. But the point is that copying it doesn't make it any larger. I should have said any copy of any ordinary file in the same format (TIFF, Word, etc) remains the same size as the original. So why can't I just stitch together two AVIs of say 1.0 Mb each and have a perfect copy with 2 Mbs? I understand the compression options in my video editing program, but why -- to be repetitive -- can't I just retain the original's compression without increasing file size?