One of the downsides of a local install is the inability to see these. It would be nice to have a utility that would "walk" through the database, check to see if the GIF is local, and if not, retrieve it from meighan.net. In a similar fashon, also allow retrieval of jpg, and pictures required for generation of an effect that was copied from another user.
Sean, do you have to pay for bandwidth, and storage? If you pay for bandwidth, perhaps consider a "Premium" option for contributors to your beer fund.