USE THESE IMAGE SEARCH SITES
Photos for Class - Searches only Creative Commons images and puts the attribution right on the image
Creative Commons Search - Searches flickr, pixabay, google, wikimedia, and youtube for CC licensed works.
Flickr Advanced Search and the CC Attribution Helper - This will create the text needed to put on a Creative Commons image found using flickr.com. Be sure to check "Only Search within Creative Commons-licensed content."
Flickr Commons - Hidden treasures from the world's public photography archives. Use the CC Attribution Helper bookmarklet.
Pixabay - Photos, drawings, and vector images all in the public domain
YOU MAY NOT USE IMAGES WITH A WATERMARK