The Sjoerd Koopman Library Postcard Collection at the University of Illinois’ ALA Archives Collection includes pictorial and photographic postcards of libraries throughout the United States and Europe. Subjects include public libraries, private libraries, academic libraries, library interiors, reading rooms, and bookmobiles. 
Currently, the collection contains 30 Pennsylvania libraries.
Check out our Carnegie Library circa 1910. Too bad they missed the ‘h’ in Pittsburgh!
Thanks to Sjoerd Koopman for letting us know about this fantastic collection!
Western Pennsylvania Law Library Association 