Public Domain images don't require attribution, making them prefect for projects of all types.
If you can't find Public Domain images that fit your needs, you can also use Creative Commons-licensed content as long as you provide proper attribution and otherwise meet the terms of the license.
The resources below offer access to music and other audio files in the public domain.
If you aren't able to find a public domain audio clip that suits your purposes, there are also many resources available to find music and other sounds that have been licensed under a Creative Commons license. Below are some of the best of these tools.
These tools will help you find public domain videos.
These resources provide access to Creative Commons-licensed video content.
Anyone can use Public Domain works without obtaining permission, making them ideal for many projects, especially projects that will extend beyond educational uses.
According to Copyright.gov, "A work of authorship is in the 'public domain' if it is no longer under copyright protection or if it failed to meet the requirements for copyright protection. Works in the public domain may be used freely without the permission of the former copyright owner."
You can use Creative Commons-licensed content as long as you correctly attribute the content to its creator and otherwise meet the terms of the license under which the content is offered. Learn more at Creative Commons FAQ.
Watch this brief overview from CreativeCommons.org.