http://www.nih.gov/news/health/oct2010/nlm-28.htm

More than 2.5 million images and figures from medical and life sciences journals are now available through Images, a new resource for finding images in biomedical literature. The database was developed and will be maintained by the National Center for Biotechnology Information (NCBI), a division of the National Library of Medicine (NLM) at the National Institutes of Health.