Although during the Nuremberg trials the excuse of "I was following orders" was deemed as non admissable and therefore every soldier on the battlefield or indeed in anywhere needs to be able to account for his her actions. It was used during the Serbia Bosnia conflict recently.
In Nuremberg there were main leaders put on trial so this argument was dismissed
Also yeah, it would be hard to say that the verdict wasn't known since the beginning there..
But generally yes you are right - every soldier does account for his actions too. But there are few points to mention:
1) killing enemy soldiers during war is not considered a crime, if done by methods allowed by conventions. So you can't say (like the guy I quoted) that every soldier should face the court like I think Osama should.
2) if you followed orders to commint a war crime, you blame it on your commander
3) if you didn't follow your orders and performed a war crime, you are responsible for that.. but keep in mind your army prosecutes you first already for disobeying.. This kind of situation happen rarely I think, since soldiers are trained to follow orders since their first steps in military.
Oh and yeah, this picture is known to be fake since long ago.. But this also show what big mistake U.S. did to bury the body in sea and showing no real proof...