ProQuest Historical Newspapers
Major city papers - scroll down for historical selections
Google News Archive
Smaller city papers
America's Historical Newspapers
Old Fulton Postcards
Even smaller city papers
ArtsStor
Mainly fine art images, but also posters and photo journalism
Library of Congress
Photos, Prints & Drawings
New York Public Library
Digital Collections
Digital Commonwealth
Photos, artifacts, and other objects from Massachusetts archival collections