The Creative Commons, (CC), is an online, non-profit group established to support the free exchange of copyrighted materials. It provides millions of royalty-free images and texts without the need to obtain permission from the copyright owner.
Items displaying the Creative Commons logo, two c's in a circle,are subject to the Creative Commons license. License requirements stipulate that the use of these resources include the proper attribute; for instance, the information acoompanying an image in the CC may state that the photographer's name must be included in a copy of a photograph.
The Creative Commons website is easily searched at http://www.creativecommons.org.