Can anyone explain to me what this picture is about? Specifically the creepy smiling guy on the left.

by Murko666

Hi! I've found this picture online and I'm wondering what it is about, I know it's about WW1, but what about the creepy guy on the left? Here's the link: https://i.imgur.com/C6PsylB.jpg

Sjoerder

A related question about the same picture, with an answer from /u/hillsonghoods: Is there any evidence that the soldier in this photo has shell shock?