This is an American Geosciences Institute (AGI) image collection. It is targeted at the public, educators, and the geoscience community. The images available are NOT for commercial use, but can be used for non-print, non-commercial purposes. More information on image use is available on their site.

This is a digital tapestry map (46.5 MB PDF file) of the lower 48 United States. It displays detailed information about the US land surface and the ages of underlying rock formations. Geologic time is shown in color.

This is a collection of >500,000 photographs, slides, glass plates, lantern slides, negatives, and sketches from the 1870s onward taken by USGS scientists during field studies. Subjects encompass a broad variety of earth science disciplines. The web site provides free downloads. USGS-authored photographs are in the US Public Domain. However, you will need to check the author credit information on the images — some of them are non-US Government and might require contacting the copyright holder to use.