Timothy H. O'Sullivan

Yes. O'Sullivan worked with Mathew Brady's Civil War photography operation before later working with Alexander Gardner. Many Civil War images were produced through these studio networks rather than by a single named photographer alone.

O'Sullivan is often associated with stark battlefield images such as A Harvest of Death from Gettysburg, published in Gardner's Photographic Sketch Book of the War. The photograph helped define the visual memory of the Civil War dead.

After the Civil War, O'Sullivan joined geological and survey expeditions in the American West during the 1870s. His photographs of canyons, rock formations, and expedition sites became important records of western exploration.

O'Sullivan's western images were made for government-backed exploration and scientific survey work, not just art. They document places such as Nevada, Arizona, and the Colorado River region during a period of U.S. expansion.