I'm a bit the same on the concept behind the painting but it's dramatic for all that, & ultimately a talking point already! But war has been with mankind since the outset of creation, & God uses it for His purposes. And the more I look at the painting the more I equally feel if Jesus was asking God to forgive anyone, it wouldn't be those in the world's armies but rather those against whom they fight, so agree with BC62 on that point too.
No reflection on the uploader meant in any sense :) +1