Many users on Flickr (the image and video hosting site) have chosen to offer their work under a Creative Commons license, and you can browse or search through content under each type of license.
Images of artworks in The Met’s collection that the Museum believes to be in the public domain, or those to which the Museum waives any copyright it might have, for any purpose, including commercial and noncommercial use, free of charge and without requiring permission from the Museum. To identify these images, look for the Creative Commons Zero (CC0) icon directly below the image.
Download royalty free stock photos and videos and share your own pictures as public domain with people all over the world. You may download, modify, distribute, and use them royalty free for anything you like, even in commercial applications. Attribution is not required.
Shutterstock, a global technology company, has created the largest marketplace for creative professionals to license content (including images, videos and music) as well as innovative tools that power the creative process.
500px is a premium marketplace for photography licensing. All of 500px’s inspiring and evocative photography is directly sourced from the world-class 500px community. Separate section of the site provides images licensed with Creative Commons.