Sometimes we miss things in the Bible, though they are right in front of us. Some of our Protestant brethren (mainly Calvinists but some other denominations as well) have an almost obsessive fear of any image associated with worship at all, thinking that all such manifestations are examples of idolatry and undue exaltation of a "graven image". This has led some fanatical elements to oppose even crucifixes and statues of Christ as idols. In other words, all images whatsoever are collapsed in this wrongheaded mentality into the category of the "graven image" in the Ten Commandments. But the Bible doesn't take this view at all. Here is one striking example:
Exodus 33:8-10 (RSV) Whenever Moses went out to the tent, all the people rose up, and every man stood at his tent door, and looked after Moses, until he had gone into the tent.  When Moses entered the tent, the pillar of cloud would descend and stand at the door of the tent, and the LORD would speak with Moses.  And when all the people saw the pillar of cloud standing at the door of the tent, all the people would rise up and worship, every man at his tent door.
Note that the pillar of cloud is:
1) a creation (water, if a literal cloud);
2) visual, hence an image;
3) thought to directly represent God Himself.
It's also a supernatural manifestation, which is a major difference compared to any true idol made by the hands of men; but that would make no difference for those who mistakenly hold that any image whatsoever associated with God is impermissible. The problem comes when God Himself expressly sanctions such images, and worship in conjunction with them, as here.
The same iconoclasts (opposers of images) have to explain away things like the burning bush (Ex 3:2-6), which is not only fire, but also called an "angel of the Lord" (Ex 3:2), yet also "God" (3:4, 6, 11, 13-16, 18; 4:5, 7-8) and "the LORD" (3:7, 16, 18; 4:2, 4-6, 10-11, 14) interchangeably. An angel is a creation (as is fire and cloud); yet God chose to use a created being and inanimate objects to visibly represent Him. Several similar instances occur in the Old Testament. Moreover, the Jews "worshiped" fire as representative of God in the following passage:
2 Chronicles 7:1-4 When Solomon had ended his prayer, fire came down from heaven and consumed the burnt offering and the sacrifices, and the glory of the LORD filled the temple.  And the priests could not enter the house of the LORD, because the glory of the LORD filled the LORD's house.  When all the children of Israel saw the fire come down and the glory of the LORD upon the temple, they bowed down with their faces to the earth on the pavement, and worshiped and gave thanks to the LORD, saying, "For he is good, for his steadfast love endures for ever."  Then the king and all the people offered sacrifice before the LORD.