A few additional notes:
While every other commandment is repeated and strengthened by Jesus in his Sermon on the Mount, the commandment against the "graven images" is not even mentioned. On the other hand, there are many other commandments given the Jews -- such as the entire dietetic law, -- that we clearly understand not to apply to Christians. Therefore the "graven images" prohibition, whether it is a separate commandment or a part of a larger one, is not binding on the Christians.
The scripture uses the word "icon" (in translation, "image") quite a bit, and always in a positive context: "we all beholding the glory of the Lord with open face, are transformed into the same image from glory to glory, as by the Spirit of the Lord" (2 Corinthians 3:18)
From "who hath bewitched you that you should not obey the truth, before whose eyes Jesus Christ hath been set forth, crucified among you?" (Galatians 3:1) we can infer that a crucifix was among the imagery of their churches, since obviously they were not present at the actual crucifixion.
The Jews didn’t even observe the graven images commandment with the same rigor that the Protestant iconoclasts do.
Just look to the Ark of the Covenant bearing the cherubim on top and the depictions in Solomon’s Temple.
The Calvinists have more in common with Islam when it comes to sacred images than they do with OT Judaism.