Creating a dynamic Chrome theme

I'm trying to build a theme extension for Google Chrome that will regularly update the background image using a remote image source (i.e. images are stored on a web server, not locally). The problem 开发者_运维百科is that themes are not allowed to contain scripting elements. Any suggestions how to work around this restriction?

If by background image you mean the background of the New Tab page, you can replace it with an html page (using an extension, not a theme, that is): http://code.google.com/chrome/extensions/override.html.