Hi, folks --
Also be sure that if the artwork is European, the copyright wasn't renewed (the EU version of our Copyright Extension Term Act did that, ours didn't). Also, if the author or estate incorporated, the period is 95 years from death. And last, be sure to check that the "image" you're using hasn't been copyrighted (how Corbis and the Bettmann Archives make their money).
On the other hand, parody is "almost" always fair use. If Disney weren't so aggressive, I'd take a clip of Pinocchio and substitute Sonny Bono's face behind the nose.
Cheers,
BobB