Functionality to actually change images Being able to find the images to change, browse images, manage the files, etc. If you can't remember where you put an image or what you called it, then The GIMP can't help you. In fact, there aren't many applications which can help you. CompuPic can, and does. With both CompuPic and The GIMP, the graphics user skips the part where he or she can't find a file.
Productivity goes up and costs go down.
If you just need to rotate an image 90 degrees, using The GIMP is overkill. Once users start using CompuPic, they almost immediately get addicted to it. Not because they're always thinking about how great it is to use it, but because if they ever don't have it, they panic. The first time this happens, users wonder how they ever did without CompuPic in the first place.