One request Rated 5 out of 5 stars
Does exactly what it says on the tin. Absolutely brilliant fact that it also adds a class to both the BODY and IMG to enable users to style it using userChrome.css or Stylish.
However, I would recommend that you add built-in options to allow users to customise the background with an image instead of the colour. Better yet, just replace the entire background-color parameter with background, for greater customisability control.
That makes a ton of sense, but the downside is that background doesn't accept completely the same syntax as background-color (the leading # for hex colors is not optional -- hopefully that's the only difference.) I can fix that with a bit of parsing, but I'm worried I'll get it wrong and break some people's config.
Ah well, I'm sure they'll e-mail and complain if that happens...