Note on reverse (below) kindly translated by xiphophilos: "Here the first Americans were captured. They are the ones with the X. Make sure to keep the postcard! On 3 November 1917, 9 Americans captured."
The first full-fledged combat involving U.S. troops happened on November 2–3, 1917, at Bathelémont, France; three were killed and twelve were taken as German prisoners of war.
One of the more remarkable pictures I've come across in recent times, for detail and poignancy. I have added notes to items that may be of interest. There is little doubt these men are not long returned from a foray at the Front.
Battle hardened German troops with nine American prisoners (marked with an "X") and an array of captured equipment.
A number of the soldiers in this picture are wearing covers on their helmets, these began to be issued in Feldgrau material in 1917.
As from 7 July 1918 the troops were advised to paint them with irregular, sharp-edged patterns of dark green, rust brown and ochre yellow separated by thick black lines.