This information was copied from The University of California Irvine's page: "Art Research: Attribution Best Practices" by Derek Quezada
Attribute an image/visual media source for presentations, papers, or other formats that do not require a specific publication style.
Try to include the following elements in your attribution
Examples for some of the most common instances where attribution might be nessesary.
Google Images
Vincent Van Gogh, Starry Night, 1889 (oil paint on canvas). Retrieved 7.27.11:
http://www.vangoghgallery.com/painting/starryindex.html
Flickr Images
Science Library, UC Irvine by askpang, 2007 (CC BY-NC-SA 2.0)
Wikimedia Commons
Featherbed Alley Printshop (2006) by Aodhdubh (CC BY-SA 3.0)