Diego Rivera, Edward G. Robinson and my father Sam Salz in Rivera's San Francisco studio (unknown photographer). The actor Robinson was there to pose for Rivera's "Pan American Unity" mural that he made for the Golden Gate International Exposition in 1940 on Treasure Island in the San Francisco Bay. In the mural, he is depicted in a scene from a movie he made then titled "Confessions of a Nazi Spy". For more on the mural here is a link: http://www.riveramural.org/home.asp?language=english
And another link with this photo on a timeline in 1940 made for Diego Rivera:
http://www.timetoast.com/timelines/diego-rivera-1940
While my father was in San Francisco at that time (1940), his portrait by Edouard Vuillard was being exhibited at the California Palace of The Legion of Honor. Robinson and his family also had their portraits painted by Vuillard while on the same trip to  Paris with my father (1939).