"unless you also clarify that the only way He could do that and still be just is if man were not made in the Image of God, which is the reason it is sin in the first place. God is not bound by His commands per se, as I said above. However, every command has a reasoned causal chain that goes back to God’s character and desires, and these are essential to Him as primal manifestation/expression/revelation of Himself both to Himself and to conditional creatures."It is because Man is made in the image of God that they are responsible to Him. God could have commanded anything - with that said His laws are said to be just, holy, and good because God commands them. However, God is not bound by those laws. Even if man obeyed the law of God completely (scripture says in Romans 3 and 10 that it is impossible due to His depravity and fallen nature) he would still be doing that which was his job as a creature. Luke says that they would be unprofitable servants because they did what they were told and what they were responsible for. All men are responsible to God because of the fact that they are creatures of God made in the image of God. This is why I say you should not imply from this that all of God's creatures deserve salvation. Salvation is a free gift of God and not something that is to be inferred on the creature.
Gordon H. Clark says, "In Christianity . . . God is supreme, and any ideas that may be required are dependent upon what God wills to think. God is the legislator, and piety is determined by his preceptive decree." - Religion, Reason and Revelation Indeed to say that God must honor his law is to subject him to a law above him. Clark also says elsewhere "Responsiblility presupposes a superior authority that rewards and punishes. The highest authority is God. Therefore responsibility is ultimately dependent on the power and authority of God. Is it just then for God to punish a man for deeds that God himself 'determined before to be done'? Was God just in punishing Judas, Herod, Pontius Pilate, and the others? The Scriptures answer in the affirmative and explain why. Not only is God the creator of the physical universe, not only is he the governor and judge of men, he is also the moral legislator. It is his will that establishes the distinction between right and wrong, between justice and injustice; it is his will that sets the norms of righteous conduct." From this I inferr that man is responsible to God because He is created in His image. One may also say that Paul says this in Romans 9 when he says that God is the potter we are the clay. The potter has supreme rights.