This is one that took me by surprise, it came as part of a mixed bag of WW1 photographs of soldier from several different countries.
At first glance I thought they were American then I checked the hat badge of the guy on the right under magnification and it is YMCA
After a Google search the only place I could find the badge was from New Zealand. The New Zealand YMCA had facilities set up in France, Belgium and the Middle East to support the troops during WW1.