In the site's css, it calls a background image, such as	

background: url(/assets/templates/interrai/images/internavi2.png) no-repeat;

These images are not getting downloaded. I have looked through similar issues
(from the distant past), but haven't found anything that helps.

I am using the GUI, with the default scan rules:

+*.png +*.gif +*.jpg +*.css +*.js -ad.doubleclick.net/*
-mime:application/foobar

How can I make this work? Thanks!