These directories are roughly organized by topic. They collect artwork from many people, over many years.
One or two were actually done by professionals, but mostly they're amateur. Where possible, the images
are in at least two forms: an actual image (JPEG, PNG, ...) and the master artwork. The images based on
3D models don't have many models accompanying them: a bunch of clipart was used and modified
and we don't have the rights to redistribute all of that. We'll slowly work out
which things we can release. For now, the models of Duke, Tux and the Paper Clip
Monster are included.