First off, love your plugin – what an easy CDN solution!
I am however having an issue – I have items in my template that are in the root directory of the site, and your plugin is rewriting those URLs as well. Also, the browser is not recognizing the favico.ico file after installing the plugin.
If you go here for example:
Scroll down to the comment box, there should be a gravatar image there, but with the plugin activated it rewrites this: