The laws governing fair use of copyrighted materials have always been hazy, and digitization and the internet have added complications galore. Here are some resources that might help you discover whether something is protected by copyright law, whether your use of it might require a license, and whether what you want to do with it constitutes fair use. This page also includes links to open source materials that you can use as alternatives to copyrighted materials.
(This page presents only general information, and does not constitute individual legal advice.)
Visit the SMU Libraries Copyright Website to learn more about copyright materials. If you have specific questions, feel free to reach out to your subject librarian, or email firstname.lastname@example.org.
Open Source Alternatives
(Note that even free sources may require attribution)
Finding Non-Copyrighted Images for Presentations (Vanderbilt)
Flickr (billions of images)
Wikimedia Commons (millions of images)
Project Gutenberg (free e-books)