Thanks Lucie, I thought Guard dog too, and an attempt to get all the cap badges in.
In the context of the calendar that picture did not horrify or disturb me at all;the girls were not terrified. Had it been from one of the camps during the Shoah, then yes it would. However, I don't look for references to the Shoah in everything.
As to the summer camp comment; I HATED summer camp at school when I was 11, and have not been under canvas for the intervening 33 years. I would not compare an unpleasant week in the New Forest with Auschwitz/Birkenau, although you may choose to.