“You’ve heard the adage that a picture is worth a thousand words, but when that picture is protected by copyright, the picture is only worth three words: cease and desist.”
from Social Media Examiner.
Please see the article — http://www.socialmediaexaminer.com/copyright-fair-use-and-how-it-works-for-online-images/
Try using the Public Domain Sherpa: http://www.publicdomainsherpa.com/index.html
An outstanding resource for public domain images and other media: http://thecavalcade.info/