Try to find the spot where the photographer was standing.
The "Colonel Donovan" named in the photo's caption is none other than World War I Medal of Honor recipient United States Army Colonel William Joseph Donovan.
From Wikipedia (http://en.wikipedia.org/wiki/William_Joseph_Donovan):
"During World War I, Donovan organized and led a battalion of the United States Army, designated the 165th Regiment of the 42nd Division, the federalized designation of the famed 69th New York Volunteers, (the 'Fighting 69th'). In France one of his charges was poet Joyce Kilmer. For his service near Landres-et-St. Georges, France, on 14 and 15 October 1918, he received the Medal of Honor. By the end of the war he received a promotion to colonel, the Distinguished Service Cross and two Purple Hearts "
Much better known as "Wild Bill" Donovan, he was a law school classmate of Franklin D. Roosevelt. Donovan, although a Republican, was a friend and confidant of Democrat Roosevelt's prior to the Second World War and on the eve of the war was entrusted by FDR to found the Coordinator of Information (COI), which would become the Office of Strategic Services (OSS), the World War II predecessor to the Central Intelligence Agency (CIA). Donovan would lead the OSS until it was disbanded by President Truman in September 1947.
The Victory Arch depicted in the photo was a temporary structure erected in Madison Square Park (note the Flatiron Building looking north though the arch) at the conclusion of World War I to honor New York's war dead. It would later be dismantled.