Here are steps for finding visual and audio materials for use in creating an open textbook ... and to evaluate whether and how you can use them. Nothing here provides legal advice about appropriate uses of specific materials. You must make your own determinations.
STEP 1
Use one of the search engines mentioned in the box below to find an image, video or audio content for which the copyright holder may give permissions for use. Look for "Creative Commons" licenses or other licenses. Creative Commons makes a variety of licenses available to content creators. For help in understanding the range of Creative Commons licenses:
STEP 2
After using step 1 to find candidate items to use for the textbook project, independently confirm with the owner of the image what the license says. (Again, not legal advice, but seems prudent or reasonable if you want given statements here, here and here.)
STEP 3
If you cannot use something you find on the web, consider linking to it. Attribute it and cite it as appropriate. While (again) this library guide does not provide legal advice, the section of this resource (Office of the General Counsel at Harvard) says that while "the law relating to links from one website to another is not entirely settled", "generally" things should be fine unless:
You can run a search and then filter to find Creative Commons licensed items. See below for more details.