Thanks for the suggestion, it is quite reasonable with the age vs the period. However, the decorations of the fellow in the photo would indicate him as a combatant, while the earlier long service ones I mentioned earlier are missing. Furthermore, bits of information that trickled through generations mentioned that he was posted in Prague in 1916-8. One could speculate that it was a military posting due to manpower shortages and the likes, however I would think the posting was on the civilian side as he was there with his family (his teenage daughter had certificates showing she finished at a couple of high school years in Prague).
I can conclude that the photo was sent by a friend or relative and the details are in a long-lost letter. Nevertheless, it is quite some detective work to reconstruct details based on undated and uninscribed photos from more than 100 years ago, but thanks to the knowledge on this forum I could put a few bits in the puzzle.
P.S. Now I feel sorry that I have opened two threads on the topic, but at first I thought there are different fellows in the photos. On closer inspection it turns out that it was true only for the last one.