This picture was taken by a British Gunner veteran in the 1920s. It shows the Newfoundland Memorial, (a Caribou), mounted on a British observation pillbox, in the village of Monchy le Preux.
This is a map of The Battle of Arras showing (1917) alliance advance 9th-15th of April.
This picture is of British troops returning from the Battle of Arras in 1917, due to exhaustion.