Marlag and Milag Nord was apparently a dual-purpose German prison camp: the Marlag side imprisoned Royal Navy personnel while the Milag side was for merchant seamen, such as James Swinnerton.
While one can see clearly that the men in these photos were not starved, they were obviously not overfed either. Because of the food they were given during their incarcaration (or more to the point, the lack of it), James Swinnerton had serious digestive ailments for the remainder of his life and died during the 1950's.
Swinnerton was a member of the British Merchant Navy which shipped supplies to Allied troops during WWII. In March of 1940, his ship, called "The Salmon Pool" which made trips from Norway to Britain, was attacked by Germans while just offshore in Norway. The British seamen jumped off the ship, swam to shore where the Germans were waiting for them. The seamen were then taken to the Milag section (an acronym for "Marine Internierten Lager" (Marine Camp Internees) of the prison camp the inmates referred to as Steinburg, located near Westertimke, Germany, where they remained for the duration of the war.
He was given this photo memory book by one of his fellow prisoners at the war’s end. Photos appear courtesy of Alison Madden, Swinnerton's granddaughter and author of the children's book, "Fred and Fiona Flea and the Crown Jewels Caper."