If you are going to chat with New York based artist Audrey Flack, she might ask you about the color of your lipstick, particularly if it is a shade of classic red as worn by iconic women, say Marilyn Monroe. In her early photorealist phase, this very girly prop shows up in likely and unlikely places, atop a dresser, near a mirror, revealing something of an obsession with the ill-fated movie star; but in the 1978 oil, “World War II (Vanitas),“ going up at auction at Christie’s next week, that very red is the color of a candle as well as a rose. Speaking about this work and its impending resale over lunch at the midtown restaurant Rare, Flack said, because of its historic reference, the painting is a work for a museum. Indeed, with its Holocaust reference, Flack juxtaposes a bright cherry on a petit four on an ornate silver dish, lustrous pearls, a butterfly, a teacup, a sumptuous gathering of life affirming objects with the grays and blacks of a row of Buchenwald inmates from a photograph by Margaret Bourke-White taken upon the concentration camp’s liberation. At an art history class at Baruch College that morning, Flack told students, back in the day, she was criticized for this odd, possibly insensitive assembling of images. But to her surprise, Holocaust survivors got it, asking her, how did you know the dream of pastries kept us alive during those dire times when all we ate were crumbs.