There's a great scene in the film Harry Potter and the Order of the Pheonix when Hogwart's caretaker, Argus Filch, is taking down an old tudor oil painting. As he twists the painting to remove it, the men in ruffs get angry, shaken from side to side, and eventually fall off the bottom.
It's visually stunning, but also emotionally engaging - it gives the viewer a real connection with the men in the painting. Imagine owning a photo frame that did this!
In fact, it must already be possible to create this effect for real, perhaps using the iPhone (since it has tilt sensors).
Surely picture animation is the next huge area for art - a way to break out of the static image and into lifelike, arresting motion. Why shouldn't the next Lucian Freud create animated paintings?
It's also one of the first digital art forms that isn't a direct copy of an analog one - unlike photography or film cartoons, you simply can't do it using paper. And it seems an even better idea than that other Harry Potter gem, the whereabouts clock.