Bolewts58 thanks for answering. Everyday is a school day 😄
I read many years ago a very plausible explanation about the number of ‘self portrait ‘ images of German MG crews. The quantity from WWI German personnel far outweigh the Allies combined. Notwithstanding the fact that German machine gunners were selected for additional qualities from the ranks of the standard infanteer, (like the Allies) but the German youth of pre-1914 were better educated, more technically aware and many had private cameras!!! This abundance of own cameras produced so many more images, and in the day, were turned into postcards. So Graf yes amazing that over a hundred years later so many survived, but so many were made! Fortunately!!!!
Mark