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."
Note: Even if a work is in the public domain, you should provide attribution for the work or at least keep a record of its source, so you or others can find it later if necessary.
Use these sites to find public domain or open access images for use in your classroom projects.
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