The problem is that these are right on the hairy edge of violation of copyright law. I hold they are "fair use" but then if someone wanted to sue me that would be a hard claim to make on a particular image although it does exist in precident.
      Because of that I am not going to make most of them downloadable. (Ever heard of screen capture? the right rat button?) There is a difference between "fair use" and distribution and making them downloadable would equal distribution. I wish to limit any potential liability.
      Someone wiser than I may be able to give a better approach to this than I. If you a specific interest contact me and lets talk about it.