Now links in descriptions are being absolutized relative to original feed URL upon fetching. This is supposed to fix missing images and broken links which are caused by feed item being moved from original feed (preprocessed feed, then friends feed and so on).
I wrote perl class that allows changing all links in HTML code in one call (will be used for some other features as well) and a subclass that absolutizes it based on some URL.
It will be my first OpenSource Perl module that goes up on CPAN – it will be available soon at http://search.cpan.org/~sergeyche/