I watched "WWI's Forgotten Photographs" a BBC Documentary from last fall. It is available free here.
I'm an amateur photographer myself, so I was intrigued to learn that WW1 soldiers in both the British and German armies frequently carried small "vest pocket" cameras, made by Kodak in Rochester, NY, USA near where I grew up.
On both sides, the early days of the war were treated as a jolly adventure. A contemporary magazine article warned deploying soldiers to save some film for the front -- not to use it all enroute! At first the British press begged soldiers for war shots, but soon the high command decided that it should control images. Personal cameras were forbidden to the Tommies and their possession could lead to courts martial. Fortunately, some soldiers persisted in recording their experiences, most especially capturing groups of friends, and, in one notable instance, those friends' graves.
German soldiers seem to have been encouraged by their officers to take pictures. I may be over-interpreting a slight impression, but the Germans are depicted as enthralled by the technological possibilities implicit in soldiers using cameras while at war. The sixteen year old soldier Walter Kleinfeldt turned out to be a master image maker. One of his shots heads this article.
The flood of amateur photos on both sides dwindled after 1916 as the war became no longer an adventure, but a brutal, almost incomprehensible slog.
The BBC documentary, viewed as an artifact of 2014, seems to me "heritage" schmaltz, excessively sentimental and florid. A British and a German photographer, descendants of WWI photographers, meet carrying their cameras at the Somme battlefield where their forebears fought, while mood music rises in a crescendo. I guess they could be thought of as icons of contemporary pan-European good feeling. I note the French don't get to participate.
The TV show made me think about why Britain seems to be so enjoying the centenary of WW1. We Yanks won't be doing that; that war was too marginal in our history (for all its very real consequences which we are still struggling with.) I wonder whether in Britain today, WWI enjoys a happy status as the one more or less modern war that seems 1) definitely over and 2) not an occasion for immediate horror or shame. The grandfathers have all died; the empire has faded away; other European states -- Germany and Russia -- suffered the worst subsequent scourges; the nation both endured and eventually triumphed. Just a guess from across the Atlantic.