Library of Congress - Prints & Photographs Online Catalog
"The collections of the Prints & Photographs Division include photographs, fine and popular prints and drawings, posters, and architectural and engineering drawings. While international in scope, the collections are particularly rich in materials produced in, or documenting the history of, the United States and the lives, interests and achievements of the American people."
"The nature of historical archival collections means that copyright or other information about restrictions may be difficult or even impossible to determine. Whenever possible, the Library provides information about copyright owners and other restrictions in the catalog records or other texts that accompany collections. The Library provides such information as a service to aid patrons in determining the appropriate use of an item, but that determination ultimately rests with the patron."