Thanks to Chris for demonstrating there why I wouldn't pay for discussion forums.

Meanwhile, seriously, install a gzip module on your webserver. HTML bandwidth requirements will probably drop to a 10th. This alone will probably only shave 2% on your bandwidth bill without optimising images and boy do they need optimising. 10 seconds with "Ulead Smartsaver Pro" and the Bush photomosaic went from 99k to 16k, without any visual quality loss. Optimise images and gzip HTML and your bill should drop by at least 80%.

You're going to be hard pushed to make me pay for your bandwidth if you're wasting it this badly.