Images in the public domain are not restricted by copyright and can be used in a variety of ways—in papers, in presentations, in published works, or in the classroom. No restrictions for use exist on materials that are truly in the public domain. Items come into the public domain for any of the following reasons:
Public domain images and collections may or may not explicitly state their status. If in doubt, contact the source of the image.
"Pondering the Public Domain" by Niagra College Libraries is licensed under CC BY 3.0 (Embedded video starts at :07)
United States government creative works, including writing, images, and computer code, are usually prepared by officers or employees of the United States government as part of their official duties. A government work is generally not subject to copyright in the United States. (This applies to the federal government not individual state governments.)
Unless the work falls under an exception, anyone may, without restriction under U.S. copyright laws:
However, this does not mean that everything found on a federal government website is in the public domain. Many image collections on government websites may include public domain and copyright protected images. Read the terms and conditions for each site visited and review the copyright information for a given image.
When creators of a work choose to waive their copyrights and dedicate their work to the public domain, they may do so using a Creative Commons CC0 License. (See the Creative Commons Licensing page to learn more about Creative Commons and their licenses.) The mark shown below used with an image may indicate the image is in the public domain.
Image from Creative Commons is licensed under CC BY 4.0
For non-U.S. government works and for images that don't explicitly indicate their status, a user may need to assess whether an image could be protected by copyright. U.S. Copyright Law has changed over time, which means that images may become part of the public domain at different times. Here are the basics:
Use these tools to make case-by-case determinations:
A user does not have to give credit for public domain images, but here are three reason why doing so is a good idea: