But they are images created from a txt file. I've not seen a program that can create non-text subtitle-like images, such as the "rabbit" from the Matrix DVD, or the familiar "MST2000" outlines (I forget what DVD that was on.) If such a program exists, that would be great!
You're probably thinking about the Ghostbusters DVD. Good commentary.
Though even better and more over the top was Brother Bear. Bad movie, great commentary. Tuke and Rut (animated moose silhouettes anyway) with Rick Moranis & Dave Thomas commenting throughout the film like MST3k meets the McKenzie brothers.
Guess that was off subject, but software that does that sort of think WOULD be awesome.