One of the P-I’s staff bloggers, Robert McClure (Dateline Earth), gathered together a lot of sites that offer photos in the public domain – meaning photos that are often available for use without violating copyright. Some are a bit enviro-oriented, he says, because that’s the nature of his blog. But you may find them useful.
Please, please, please, follow his cautions however. Not everything on all these sites is available for use in the public domain, so be certain you check on anything you use.
Here’s his list:
Note: If you're going to use these, you have to make sure you carefully read and understand the usage terms. Only use the ones that are absolutely and unquestionably public domain.
Everything at this site is public domain.
Below are sites that are government collections and, unless otherwise noted, are usually available for use. But check carefully to make sure a photo is not copyrighted:
(and how to link to NASA images:
US Dept of Interior: http://www.doi.gov/photos/gallery.html
Natl Biological Information Infrastructure: http://images.nbii.gov/
US Fish & Wildlife Service: http://www.fws.gov/pictures/
Va. Institute of Marine Science (Part of the College of William & Mary):
energy related: http://www.nrel.gov/data/pix/searchpix_visual.html
yellowstone NP: http://www.nps.gov/yell/photosmultimedia/index.htm