The museums behind the paintings

• National Gallery of Art, Washington 980 paintings The nation's collection, from Italian Renaissance panels to American folk portraits and French Impressionism.
• The Metropolitan Museum of Art, New York 941 paintings European masterpieces, the American Wing and the Robert Lehman Collection, all shared as open-access images.
• Art Institute of Chicago 347 paintings One of the great Impressionist and Post-Impressionist collections, with American and European paintings beside it.
• Cleveland Museum of Art 232 paintings European and American paintings from a museum that shares its public-domain collection freely, with print-size images.

Each painting page links to the museum’s own record of the work, which is the authority on its title, date and size. What CC0 lets you do with the images is on the image license page.