"In this post, we’ve created a list for you of awesome websites that have free stock photos. This is not the end all – be all of sites and if you find others, please feel free to list them in the comment section. Note: Most of these images fall under a creative commons license (just make sure you attribute properly) or are old enough that the photos have returned to the public domain. (This happens once the copyright on an image expires.)" - Maitani

Found via Another Word For It http://tm.durusau.net/?p=59044 - Maitani