I observed that the page tree took a while to render in IE6 and identified the problem as a Javascript fix for IE's poor transparent PNG support.  Executing this script took some time and to speed things up, I tweaked the PNGs themselves and disabled the script.  The result is that, although IE6 will not display nice transparent backgrounds for the images, the pages will come up much faster on IE6!

This change is forward-compatible to IE7, which does have reasonable support for transparent PNGs anyway and wouldn't need to make use of the script.

If you notice any images with black backgrounds in IE6, please let me know, I might be able to fix them.