Thank you Michael for your translation
According to my grandfather's records, Stanislaus Kowalinski died on 20 December 1917 in Marienburg. Family lore has it that he was killed by machine gun fire, so I assumed he was near The (or a) Front. I am unable to find him listed in the http://www.volksbund.de/
'soldier search' page, but the database there is incomplete. I don't know in which year the photo was taken, it is quite possible it was taken somewhere completely removed from Marienburg. When I posted the photos here I was only trying to figure out what the uniforms were! Now I'm even more interested in these men.
re Duckman's questions, yep, I'm pretty understanding of the whole Prussia/Poland border changes, I'm researching the genealogy of my Polish/Prussian side.
I think I'm on the wrong war forum to be writing about Stettin in 1939! But to answer your question, my grandparents were from Bydgoszcz. When Germany invaded Poland they were travelling or visiting somewhere, possibly in Szczecin. My grandfather's uncle and cousins had moved there prior to 1936. My grandfather worked in a post office in Bydgoszcz, and hearing that the Soviets were in Bydgoszcz, and being a government employee he was likely to be killed if they returned there, I think he applied to the Germans to be able to stay in Stettin near his extended family - and it would have helped that his cousin was off being a soldier on the front lines, I'm sure. Pop saved a lot of his official documents from that time, I'm just starting to go through them to figure out what they are.