License, verbatimPD
The National Gallery of Art: open access image with no usage restrictions under the NGA's open access policy (openaccess=1 in the Gallery's published_images dataset).
Charles Nègre, Nadar, André Jammes. Planche X – Portrait du Prince Adam Georges Czartorisky, d'après Nadar (Plate X – Portrait of Prince Adam Georges Czartorisky, by Nadar), c. 1857, printed 1982. National Gallery of Art, Washington.