William Redish Pywell was a 19th-century American photographer. He first worked for Mathew Brady and Alexander Gardner making a photographic record of the American Civil War, this work was published by Gardner in 1866 as "Photographic Sketch Book of the War" Vols. 1 & 2. After the war, he traveled with George Custer as the official photographer of the 1873 Yellowstone Expedition. He also accompanied Alexander Gardner on the Kansas Expedition.