Check out Open-i (http://openi.nlm.nih.gov/), the National Library of Medicine’s new image retrieval project. Still in Beta, this new service “aims to provide next generation information retrieval services for biomedical articles from the full text collections such as PubMed Central.” Powered by the search engine Essie (that supports ClinicalTrials.gov) a search is able to retrieve both the text and images in the articles.
Other features include viewing search results in a citation list or image grid, limiting by image type (CT Scan, MRI, Photographs, etc), by subsets such as basic science, clinical journals, ethics or systematic reviews, by specialties, and more.
For more information go to http://openi.nlm.nih.gov/about.php or visit the Frequently Asked Questions page.
To find other health sciences image sources go to the UC Libraries Media guide http://guides.libraries.uc.edu/healthsciences