Free Picture/Photo Sources

These sites are considered 'free' picture sources, but you need to read the terms of use to each site, to protect yourself. At most, all you may have to do, is to acknowledge the author of the picture by placing a link below the picture.

http://search.creativecommons.org/ A search engine for Creative Common licensed pictures.
http://gallery.hd.org/index.jsp DHD Multimedia
http://www.everystockphoto.com/ Every Stock Photo. Searches Free Photo sites.
http://www.flickr.com/ Lots of pictures to choose from, but watch out and head the licenses.
http://www.freedigitalphotos.net/ 1,000's of free photos to choose from, nice previewer.
http://www.freefoto.com/ Photos listed Geographically and by subject.
http://freerangestock.com/ Totally free Stock Photography and Textures.
http://www.morguefile.com/ The place where old projects and picture campaigns go to die.
http://www.openphoto.net/ Several categories to choose from.
http://www.pdphoto.org/ Thousands of free royalty-free pictures here. Link back to this site.
http://www.photorack.net/ Free stocked Photos.
http://www.public-domain-photos.com/ 5,000 free pictures and 8,000 free cliparts.
http://www.publicdomainpictures.net/ Many pictures free, including commercial, with a link back to this site.
http://www.sxc.hu/ Nice mouse over previews of each picture.
http://www.unprofound.com/ Choose photos by color or search for them.
http://visipix.dynalias.com/index_hidden.htm Just supply a link and you can use the picture.
http://wikipedia.org/ Note the terms for each picture.
http://woophy.com/ Large selection. Can be used non-Commercially on a website.

It's best to treat each individual picture as it's own unique license. Don't take for granted that just because one picture on a website is free, that they all are. In the case for the above sites, most authors just want recognition for their work. Some will even allow you to crop the picture or to alter it in some slight way, but again, make sure that you read the terms of use for each one.