There isn’t much reason to add to the excellent and engaging — but lengthy — debate on other blogs about a possible copyright infringement claim against the designer of a very popular poster of President Obama, which is based on a photo taken by an AP photographer.
My own view is that the poster is extremely different from the photo. That may mean there is no substantial similarity — although the actual image was copied, in a mechanical sense, which may mean under the literal terms of the Copyright Act that substantial similarity isn’t relevant because at some point in the production process the poster artist presumably made an exact duplicate.
Even so, however, I think that the degree of transformativeness points toward fair use. How sure am I? Give me a break, this is fair use; there are no sure things.