A fast image search engine that has excellent filters to assist you with finding images free for use. Includes CC filter & safe search filter (hides inappropriate content)
Many Flickr users have chosen to offer their work under a Creative Commons license, and you can browse or search through content under each type of license.
A media file repository making available public domain and freely-licensed educational media content (images, sound and video clips) to everyone, in their own language. Unlike traditional media repositories, Wikimedia Commons is free. Everyone is allowed to copy, use and modify any files here freely as long as they follow the terms specified by the author; The Wikimedia Commons database contains material licensed under the Creative Commons.