* Images behind the clock. Several take turns: an animated GIF plays through
  once, a still holds for a chosen time, one cross-fades into the next, and six
  fit modes cover every shape. Sort them by name or date, rename them, arrange
  them by hand, or select many and delete them together.
* An image inside the text: the digits become a window onto a picture, and an
  animated GIF loops in there.
* Two sliders set how much room the time takes, one per orientation.
