This image matches one in the U.S. National Archives credited to photographers Arthur S. Mole and John D. Thomas, captioned as follows: "18,000 Officers and Men at Camp Dodge, Des Moines, Iowa. Colonel William Newman, Commanding. Colonel Rush S. Wells, Directing." The picture was taken in July 1918.
P.S. Une autre source donne, comme date, le mois de septembre 1918.