I use css sprites for all of my wiki. It lets me cut down on file sizes and use only a few images. I define each sprite in the themes tab on the css override section. Currently that page is 8000px long because of it. Meaning, I have to scroll all the way back up each time I want to save. My wrist hurts. I'd love to see a sticky to the top of the page save button. Off the top of my head, that page and the navigation page would benefit from this.