This photograph of Colonel Charles W Roberts is in the collection of Civil War Photographs at the Library of Congress. Roberts commanded the 2nd Maine Infantry on the Maryland Campaign.

Lieutenant Colonel Joseph H Barnes led the 29th Massachusetts Infantry, part of the Irish Brigade, in their assault on the Sunken Lane at Antietam. His photograph is from a carte-de-visite (CDV) sold on ebay in 2016.

Colonel James McQuade commanded the 14th New York Infantry at Antietam. This photograph is in the Library of Congress.

This postwar photograph is of Henry Lawrence Eustis, professor of engineering at Harvard’s Lawrence Scientific School (now School of Engineering and Applied Sciences – SEAS) from 1849 to 1862, and from 1864 to 1885. It’s online thanks to SEAS.

A graduate of Harvard (1838) and first in his class at West Point (1842), Colonel Eustis commanded the 10th Massachusetts Infantry on the Maryland Campaign.

This is a photograph of Colonel Theodore B Gates from the Library of Congress. As Lieutenant Colonel he led the 80th New York Infantry (20th New York State Militia) in action on the Maryland Campaign.