The existing API was better suited to direct color than indexed
color. The NES visualizer was using a slightly silly hack to avoid
duplicate colors; this has been removed.
Visualization animations are now exported as animated GIFs. The
Windows stuff is a bit lame so I threw together some code that
stitches a bunch of GIFs together.
The GIF doesn't quite match the preview, because the preview scales
the individual frames, while the animated GIF uses the largest frame
as the size and is then scaled based on that. Animating frames of
differing sizes together is bound to be trouble anyway, so I'm not
sure how much to fret over this.