Free images are a boon for WordPress blogs. As you know we are very visual people. Images on our sites grab attention and make the site more interesting. WordPress makes it easy to upload images to your blog posts. It is easy to find free images for your site.
3 great sources for finding free images.
Creative Commons Search: http://search.creativecommons.org/
“Do not assume that the results displayed in this search portal are under a CC license. You should always verify that the work is actually under a CC license by following the link. Since there is no registration to use a CC license, CC has no way to determine what has and hasn’t been placed under the terms of a CC license. If you are in doubt you should contact the copyright holder directly, or try to contact the site where you found the content.” CC Search