Images are generally not copyrighted, however in case of commercial use beware:
"If the NASA material is to be used for commercial purposes, including advertisements, it must not explicitly or implicitly convey NASA's endorsement of commercial goods or services. If a NASA image includes an identifiable person, using the image for commercial purposes may infringe that person's right of privacy or publicity, and permission should be obtained from the person."
"Photos in our Image Gallery are available free of charge and are copyright-free, public domain, images unless otherwise indicated. Please note: these photos may not be used to infer or imply ARS endorsement of any product, company, or position.
When using these photos, we ask that you credit the Agricultural Research Service. You may use one of the following credit lines: Photo by (photographer's name), USDA Agricultural Research Service. Photo courtesy of USDA Agricultural Research Service.
Photo courtesy of USDA ARS."
"Most NOAA photos and slides are in the public domain and CANNOT be copyrighted.
There is no fee for downloading any images on the NOAA Photo Library. Educational use is encouraged as the primary goal of the NOAA Photo Library is to help all understand our oceans and atmosphere so as to be better stewards of our environment for future generations.
A few photos in the NOAA Photo Library that are known to have copyright restrictions are so noted in the caption information associated with those images.
Credit MUST be given to the National Oceanic and Atmospheric Administration/Department of Commerce. Where a photographer is noted, please credit the photographer and his/her affiliated organization as well."
This page features items from the Library's digital collections that are free to use and reuse. The Library believes that this content is either in the public domain, has no known copyright, or has been cleared by the copyright owner for public use.
These sets are just a small sample of the Library's digital collections that are free to use and reuse.
"Unsplash was formed as the antithesis to the stock media experiences available at the time. Instead of vast libraries, licensed and presented for commercial buyers, we focused on pushing the impact of photography further than ever before by making original, high-resolution images available for anyone to use for anything."
"The Gender Spectrum Collection is a step toward improved representation of one of the world’s most diverse and historically most misrepresented communities, but one photo collection for one outlet is not enough. These images have been made available to other media organizations through a Creative Commons license. We encourage media outlets to use them widely and responsibly, and to commission their own nuanced depictions of trans and non-binary people whenever possible."
7,000 images related to health promotion, physicians, AIDS prevention and control, etc. "Works produced by the U.S. government are not subject to copyright protection in the United States. Any such works found on National Library of Medicine (NLM) Web sites may be freely used or reproduced without permission in the U.S. Please acknowledge NLM as the source of the information by including the phrase 'Courtesy of the U.S. National Library of Medicine' or 'Source: U.S. National Library of Medicine.'"
"With new platforms and tools, you have easier access to more than 3 million 2D and 3D digital items from our collections—with many more to come. This includes images and data from across the Smithsonian’s 19 museums, nine research centers, libraries, archives, and the National Zoo."
"Although we do our best to offer only Illustrations that are considered public domain in most countries, copyright laws vary from one jurisdiction to another, and you agree that you are solely responsible for abiding by all laws and regulations that may be applicable to using the Illustrations. While we endeavor to provide enough information to make that process as easy as possible, we cannot guarantee that this information is accurate."
"All Texts (original works and translations) that do not belong to the public domain are published under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License."