Grabbed a whole bunch of images as potential backgrounds. These come from Huge and Random and from a few more web searches.
Rename a few images and use the first half-dozen slides.
Now includes a bunch of slides. The ones with no text are not appearing, and sometimes the slide doesn't advance when I ask it to. I think it is changing back to the same slide.
Adding a whole bunch more slides. And fixing image names. May still have some wrong.
Now have slides for all images that have names (as opposed to numbers).