Widely regarded as the “mother of American modernism,” Georgia O’Keeffe was known for her looming and luminous flowers, dramatic New Mexico landscapes, bleached skulls, and New York City skylines. After the death of her husband, the photographer Alfred Stieglitz, in 1946, she acquired two cameras and learned to use them with help from a friend, the photographer Todd Webb. She studied the arrangement of forms, taking snapshots of those things she had painted in the past—the same skulls, flower petals, and cityscapes. In the first exhibition devoted to O’Keeffe’s photography, nearly 100 photos, beginning in the 1950s, are on view along with a selection of her drawings and paintings. —E.C.