Image*After is a large online free photo collection. You can download and use any image or texture from our site and use it in your own work, either personal or commercial.
The Morgue File contains free high resolution digital stock photographs and reference images for either corporate or public use.
Flickr’s Creative Commons pool has all the photos people are sharing on flickr. Search by the type of CC license.
Stock.xchng has several hundred thousand photos.
Picture Station has a more limited selection.