Adding to my initial collection of Image Galleries, I created a sample gallery of chess positions called:
Although the underlying software doesn't handle GIFs as well as JPGs, the chess diagrams in the gallery are usable. They were originally made for a two part puzzle contest on the About.com Chess Forum: Puzzle Contest no.1 (plus A difficult puzzle), and Puzzle Contest no.2.
I also tried multipage gallery navigation for the first time. It looks somewhat clunky, but there isn't much I can do about it, except keep all the thumbnails on one page.
Next gallery: a tutorial.