undetected links within theme files

If a theme includes a file that is hosted on another domain, it is not being detected. I found this out only when seeing odd load and photo not being displayed.

-png file embeded in theme option section
-java script widget from third party

I believe plugin only look for “a href” but suggest that it searches for all URLs.

http://wordpress.org/extend/plugins/tac/