Imho, to find reliable link or photos isn't so trivial as it seems. Some times i was stuck in "funneh" photos, what was with wrong data or wrong place.
Though that isn't SO insurmountable problem.
One photo from russian archives - german soldiers, dated december of 1942 in Stalingrad (maybe somewhere near Stalingrad).
How proof that is, i don't know. And when even proof, maybe only small part of all soldiers.
But at same time, i doubt also that we can use as proof looks of german POW. There was some reasons.
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E: OK, now one pics about fresh german POWs....Described as february 1943 in Stalingrad, POWs from 11th German Corps.