Finding free high-quality images can be difficult and confusing at times. Fortunately, everything you find on Photl is free to use in just about any manner that a teacher or student could think of. The only prohibited use that I read was that you cannot sell the images themselves, otherwise you can use them however you see fit. To find images you can search by keyword or browse through the tag cloud.

Applications for Education
Photl is a great collection of images that students can use in their digital presentations. The best part of having students use Photl is that you don’t have to worry about copyright infringement.