My mirror doesn't include downloaded images but just references the images URL. 
But the reason I'm mirroring the site is that I want to take it down from the
internet--so as soon as I take it down my mirror won't be able to display any
of the images.

I've got +*.gif in the scan rules.  In fact, I've tried everything I could
think of (including taking this out) but even if I leave all default settings
this still happens.  Really strange.  Is it something obvious?
I've been reading the forums for about an hour but can't find anything on
this.