The following comes from Catholic Answers:
"Catholics worship statues!" People still make this ridiculous claim. Because Catholics have statues in their churches, goes the accusation, they are violating God’s commandment: "You shall not make for yourself a graven image or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth: you shall not bow down to them or serve them" (Ex. 20:4–5); "Alas, this people have sinned a great sin; they have made for themselves gods of gold" (Ex. 32:31).
It is right to warn people against the sin of idolatry when they are committing it. But calling Catholics idolaters because they have images of Christ and the saints is based on misunderstanding or ignorance of what the Bible says about the purpose and uses (both good and bad) of statues.
Anti-Catholic writer Loraine Boettner, in his book Roman Catholicism, makes the blanket statement, "God has forbidden the use of images in worship" (281). Yet if people were to "search the scriptures" (cf. John 5:39), they would find the opposite is true. God forbade the worship of statues, but he did not forbid the religious use of statues. Instead, he actually commanded their use in religious contexts!
God Said To Make Them
People who oppose religious statuary forget about the many passages where the Lord commands the making of statues. For example: "And you shall make two cherubim of gold [i.e., two gold statues of angels]; of hammered work shall you make them, on the two ends of the mercy seat. Make one cherub on the one end, and one cherub on the other end; of one piece of the mercy seat shall you make the cherubim on its two ends. The cherubim shall spread out their wings above, overshadowing the mercy seat with their wings, their faces one to another; toward the mercy seat shall the faces of the cherubim be" (Ex. 25:18–20).
David gave Solomon the plan "for the altar of incense made of refined gold, and its weight; also his plan for the golden chariot of the cherubim that spread their wings and covered the ark of the covenant of the Lord. All this he made clear by the writing of the hand of the Lord concerning it all, all the work to be done according to the plan" (1 Chr. 28:18–19). David’s plan for the temple, which the biblical author tells us was "by the writing of the hand of the Lord concerning it all," included statues of angels.
Similarly Ezekiel 41:17–18 describes graven (carved) images in the idealized temple he was shown in a vision, for he writes, "On the walls round about in the inner room and [on] the nave were carved likenesses of cherubim."
The Religious Uses of Images
During a plague of serpents sent to punish the Israelites during the exodus, God told Moses to "make [a statue of] a fiery serpent, and set it on a pole; and every one who is bitten, when he sees it shall live. So Moses made a bronze serpent, and set it on a pole; and if a serpent bit any man, he would look at the bronze serpent and live" (Num. 21:8–9).
One had to look at the bronze statue of the serpent to be healed, which shows that statues could be used ritually, not merely as religious decorations.
Catholics use statues, paintings, and other artistic devices to recall the person or thing depicted. Just as it helps to remember one’s mother by looking at her photograph, so it helps to recall the example of the saints by looking at pictures of them. Catholics also use statues as teaching tools. In the early Church they were especially useful for the instruction of the illiterate. Many Protestants have pictures of Jesus and other Bible pictures in Sunday school for teaching children. Catholics also use statues to commemorate certain people and events, much as Protestant churches have three-dimensional nativity scenes at Christmas.
If one measured Protestants by the same rule, then by using these "graven" images, they would be practicing the "idolatry" of which they accuse Catholics. But there’s no idolatry going on in these situations. God forbids the worship of images as gods, but he doesn’t ban the making of images. If he had, religious movies, videos, photographs, paintings, and all similar things would be banned. But, as the case of the bronze serpent shows, God does not even forbid the ritual use of religious images.
It is when people begin to adore a statue as a god that the Lord becomes angry. Thus when people did start to worship the bronze serpent as a snake-god (whom they named "Nehushtan"), the righteous king Hezekiah had it destroyed (2 Kgs. 18:4).