I make and sell button badges, which are usually just slogans though feature the occasiaonal pic or logo. I have been wondering about adding a few badges with pics of famous or infamous people and assorted catchphrases or insults but I was wondering about the copyright law aspect.
For example, if I want to make a badge with a picture of George Bush and the caption 'Derbrain of Texas' (BTW my actual work is a little more subtle and credible than that) and I cut and scan a picture of his face from the first place I find it, am I breaching copyright and if so how would whoever owned the copyright on the original pic prove that it was their picture I had pinched?