The gold standard for searching for and finding free photos with citation continues to be Compfight. Even better, the Compfight Plugin connects with your blog, allowing you to search for photos from the comfort of your blog dashboard as you write your posts.

Next up, Photos for Class, provides you with an easy-to-use search engine to find great photographs. As an added bonus, the attribution is actually automatically included at the bottom of the photo.

Finally, if you’re searching by color scheme, Tin Eye Labs, allows you to search for free photos by color scheme (up to 5 colors).