The Web is an excellent source of health-related images and many images are freely available for the purposes of teaching, studying, presenting and other educational activities. The use of images, even for educational purposes, is governed by the stated terms of use of each website and subject to U.S. Copyright Law.
Permission may need to be obtained to use images in teaching and presenting, and utilizing images for the purpose of publication commonly necessitates permission from the publisher or copyright holder.
Government materials are in the Public Domain. For public domain images, there is no copyright, no permission required, and no charge for their use. The majority of the images in these collections are in the public domain, but a few include images that may be protected by copyright. In those cases, it will be posted on the website's main page. For those sites it is important to select carefully if you do not want to obtain permissions for use.