The demo comes with 5 built-in images, 3 game rule sets and 2 bonus songs. It also has a few other limitations.
The demo download is about 3.8 megabytes (~20 minutes on a 28.8Kbps modem, ~10 minutes on 56.6Kbps, .., less than 2 minutes on the average dsl connection)
The full version on the other hand comes with over 30 images and can play any (jpeg) image you have on your disk. It
comes with 18 build-in rule sets and allows you to create any rule set you like. It also has 8 terrific songs specifically composed for the game.
After you purchase the full version you will be sent a special download link.