Question for our filmmaking DUers (permissions for images)

[Plaid Adder]

Y'all who are out there making flash films for internet distribution: What do you do about getting permission to use the images? I ask because a guy in Australia has made a digital film out of one of my webpages (The Asshole THeory of Government, http://www.plaidder.com/crackpot.htm#asshole) and he is reluctant to make it available on the web because he doesn't have rights to some of the images he used (most of it's still photos of historical assholes, Hitler, Mussolinin, Nixon, etc.). However, the film is not going to be sold, so I thought maybe distributing it for free over the web would fall under the category of "fair use" and not require permissions. However, WTF do I know? Nothing. That's why I'm asking you guys.

Any of you who are into making little movies and distributing them on the web, what do you do about getting permissions for the images you use?

Thanks in advance,

The Plaid Adder