Usable Non-Copyright Images

I found a great site - Yellowstone Digital Slide File. Owned by the government, great images from the park have been scanned and placed here for both the media and the public to use free of charge with proper credit. They are public domain.

Here is a link to an image that I used on my website.

For educators (developers), this is a great resource. The images are beautiful and high quality. The only concern about these images is that since they are scanned, they are quite large. Once someone shows you this website, you need to learn how to resize it properly.