These are image collections that are free for educational use. Please carefully read the copyright notices and disclaimers before use; some sites have detailed instructions and conditions on the use of the images.
SMART - Servier Medical ART: An image library that offers a growing collection of images, primarily illustrations
American Society of Hematology Image Bank: An image library that offers a comprehensive, growing collection of images relating to a wide range of hematology topics (requires free account registration)
BioMed Search: By Alex Ksikes, BioMed Search indexes over 1 million images from biomedical articles. Included are image captions with citations.
CDC: Public Health Image Library: Public Health Image Library (PHIL) is an extensive collection of still images, image sets, and multimedia files related to public health. Most images are in public domain and free of restrictions; however, some are copyright protected.
HEAL: Health Education Assets Library: HEAL is a digital collection of educational materials for the health sciences. "The Health Education Assets Library (HEAL) is a digital library that provides freely accessible digital teaching resources of the highest quality that meet the needs of today's health sciences educators and learners."
HONmedia: "HONmedia is a unique repository of over 6,800 medical images and videos, pertaining to 1,700 topics and themes. This database has been created manually by HON, and new image links are constantly being added from the world-wide Web.
The Human Brain Atlas: " In this atlas, you can view MRI sections through a living human brain as well as corresponding sections stained for cell bodies or for nerve fibers...Comparing MRI images with stained sections from approximately the same level can greatly increase understanding of the internal architecture of these brains."
Medicine and Madison Avenue: A Duke University collection of "over 600 advertising items and publications dating from 1850 to 1920, illustrating the rise of consumer culture and the birth of a professionalized advertising industry in the United States."
National Eye Institute: Photos, Images & Video: "Items here are not copyrighted. However, credit as follows: National Eye Institute, National Institutes of Health (except where indicated otherwise)."
National Library of Medicine: Images from the History of Medicine: "The collection includes portraits, photographs, caricatures, genre scenes, posters, and graphic art illustrating the social and historical aspects of medicine dated from the 15th to 21st century."
RedAtlas.org: "The 'Recognizing Eye Disease' or 'Red' Atlas website is a free, electronic atlas of eye disorders designed to help ophthalmologists and optometrists-in-training learn to identify eye diseases through pattern recognition.
Visible Body: "The Visible Body includes 3D models of over 1,700 anatomical structures, including all major organs and systems of the human body."
Wikimedia Commons - Medicine: The medicine section of a large database of freely usable media files to which anyone can contribute.