But man.. if it works that well most the time, that'd be sweet.
I don't think it'll work well with uneven and unsymetrical images though. It'd be impossible. Such as a picture of a skyscraper which changes halfway up, but you missed the top half, so used that tool they just showed - it'd just be a mirror image of the bottom half of the building.
Then again, that isn't at all what it's designed for in fairness.