I have been thinking about this and I was wondering how hard it would be to have some kind of translation or filter of a tag that got transformed into the directory of the current course, i.e.
Would get transformed into
<img src="../../file.php/2/if_flow.png"> (or whatetever the course dir is).
I was just looking at the filter mechanism as a potential way of doing it. Any ideas/feedback name of any filter gurus?