Most of the time the OT mentions "molten images" .... as in metals cast into idols etc.
And bowing down to worship them is the real issue (the way I read it anyway)
(Personally) I do not feel a crucifix worn around the neck is an idol or a graven image of something in heaven. It is a man made trinket identified with Christ , it is not an idol representing a false God
Yet I confess to having great concern when I see people who kneel and worship at large crucifix statues , or statues of Virgin Mary etc ... it looks like idolatry to me , and has the appearance of a graven image cast in metal or plaster or whatever.
I have been in churches where there is a large cross at the front of the room and I have kneeled there to pray without any concerns ... If I felt it was wrong my only option would be to turn my back to the cross to pray , but that seems even more wrong
I think idolatry has to exist in the persons mind before it truly is idolatry
Some sects like the Amish and Hutterites take it much farther and feel even a photograph of themselves is a graven image
Sounds silly at first , but then we see some dictatorships in the world where the dictator has his picture plastered all over the country and the loyal followers bow down and give homage to it (the picture)
Just some thought from me
Best wishes