12 million historic copyright-free images. The photos and drawings are sourced from more than 600 million library book pages scanned in by the Internet Archive organization.

The Getty makes available, without charge, all available digital images to which the Getty holds the rights or that are in the public domain to be used for any purpose. No permission is required.

Royalty free clip art and images.

The U.S. National Gallery of Art hosts more than 25,000 images of famous and not-so-famous works of art. Nearly all of the images can be downloaded and re-used for free. NGA Images also allows you to register and create online collections of images. The collections are called lightboxes.