Thompson is marked with the initials "RET"

"Officers & ladies of the 7th Cavalry, Fort Abraham Lincoln, 1875. From top left: Bloody Knife, Libbie Custer, Margaret Custer Calhoun, 1st Lt Algernon Smith, 1st Lt James Calhoun. Lower Rows: 1st Lt Tom Custer, Nettie Smith, Emma Wadsworth, Herbert Swett, 2nd Lt Richard Thompson, Capt Myles Keogh, Nellie Wadsworth (rumored to have an affair with Col. Custer), Mrs Myles Moylan, Boston Custer, Capt Stephen Baker, Emily Watson, Lt. Col. George Custer."