These sites offer free-to-use images. Bing and Google sites will need to be limited to "free to use" to limit the results correctly. To avoid plagiarism make sure you cite/give attribution to the author.
Search for free content in the public domain and under Creative Commons licenses.
This portal features content that is free to use and reuse. The Library of Congress believes that this content is either in the public domain, has no copyright, or has been cleared by the copyright owner for public use. Each set is based on a theme.
A collection of over 1 million public domain images from digitized copies of 17th, 18th, and 19th-century books.
These are lo-res digital images from the San Diego Air and Space Museum's Library and Archives, which houses over one million aviation-related photos, slides, and transparencies.
On the lower right of the search page, select Settings. On the Settings page, select the Advanced Search option. Enter the name of the image searching in the "find images with...field. Next, go to usage rights and select Creative Commons Licenses then choose the Advanced Search button.
Find thousands of freely licensed digital books, artworks, photos, and images of historical library materials and museum objects.
Enter your search. On the search results page, use the drop-down menu under "License" to filter search results.
Provided by the Centers for Disease Control and Prevention. Types of image categories/collections include influenza, natural disasters, environmental health, bioterrorism, health behaviors, and more.
Freely usable images