That photo is clearly staged. The mortar has no aiming mechanism.
Good special effects I must say then.
No sh*t there's no aiming mechanism. That's a 60mm mortar being fired *not* from the standard baseplate with aiming device, but from the "commando" baseplate. The technique the mortar gunner is using is called a "hipshoot," in which one just kinda points the mortar in the target's general direction. The 60mm mortars don't have much range anyway, so it's reasonably accurate.
The photo's not staged.
Actually there is. It is right by the guys thumb on his left hand. It is so basic as to just about qualify as not being there at all. It is a flat piece of metal on the right side of the tube that can be adjusted for the degree of inclination desired for the tube. There is a SMALL spirit or bubble level on the rear left side of the flat metal sight. The flat metal sight is bent up 90* on each end. The forward end has a peak or point and the back end has a notch, forming a sight pic that looks sort of like this....
-^- (aiming) or |___________| right side view.
You preset the degree of inclination for the tube by adjusting the flat metal sight, point the tube in the general direction as it is impossable to observe the bubble in the level while looking down the sight and then adjust the angle of the tube by centering the bubble in the level. You can see in the first pic how the guy holding the tube is looking down at his hand, that is where the "sight" is. Good luck hitting anything.