Do you know the difference between a citation and an attribution? Check out the University of California - Irvine's guide to help you decide whether to cite or attribute your image.
The rules of fair use aren't as cut and dry as they may seem. Check out the Ethical Use & Copyright page for more information about what constitutes fair use. Includes easy to use checklists to help you determine if you're use is fair.
For in-depth information on how to cite images, visit:
This Code of Best Practices provides visual-arts professionals with a set of principles addressing best practices in the fair use of copyrighted materials. It describes how fair use can be invoked and implemented when using copyrighted materials in scholarship, teaching, museums, archives, and in the creation of art.