pics4learning
Thousands of safe, free images for classroom use
microsoft
Clip art and photographs from Microsoft Office
public-domain-image
Public Domain Images are not copyrighted or restricted in their use.
4freephotos
4 Free Photos are free, public domain photos!
photopin
Photo Pin is a collection of creative commons photos.
edupic
Photos and graphics for educational use
si
Smithsonian Wild has great photos of wildlife in their natural habitats
humanline
Humanline is a visual library about history, art, and science