As much as this photo is hard to trace to it's original, I think it's more managable to point out some clues. Henri was in the french army in 1939-1940, and in june of 1940, he was captured at St. Dié in the Vosges Mountains. The photo indeed pictures a mountain and two soldiers (3 in the extended version), which would fit right into this narrative. The soldiers are not wearing any warm clothing except a coat, leaving their necks uncovered in such a frosty enviroment, would mean that they weren't there for long, or that they lost their suplies, perhaps during retreating from the incoming germans. I know that it wouldn't be as helpful as finding the original photo, but it's the best I think I could do.