Roy Lichtenstein ranks among the most celebrated artists of a postwar movement known as Pop Art, a populist revolt against the high-minded, abstract styles of the prior generation. Starting in 1960, a few commercially trained illustrators began ironically exhibiting paintings to replicate familiar images from advertising, packaging, publishing, and filmmaking. Andy Warhol famously began painting and repainting Campbell’s soup cans. In comic book style, Roy Lichtenstein’s 1964 “Hot Dog” portrayed a quintessential summer snack as heroic — or villainous — as a comic book character.