I work at the Natural History Museum, London. The Darwin image was used in our Big Idea Exhibition from November 2008-April 2009. The image of Charles Darwin is not officially available online, it was made specially for the exhibition but if anyone is interested in using the Darwin image, we can license it under the NHM copyright. Please contact the museum Picture Library [link] or contact us on 020 7942 5376/6547....Many Thanks!