First, we must point out that God made no physical form for us to see in the OT. When Jesus came, we now do have a physical form of God to look for. For the Israelites, since they have not had a picture of God, they could build statues or images that could be anything. It could be a beast, a fish, a bird, etc. In Deut. 4:17-19 we see this happening.
Deut. 5:8 says "Thou shall not make a graven image". This refers to idol worship. Catholics worship God, not the images that represent Him.
Going further back in Exodus, we read in 25:18-22 and 26:1,31 that God instructed an image of a golden cherubim be built. The Israelites did not worship this cherubim. Rather, the cherubim disposes their minds to the supernatural and thus draws them to God. Sounds Catholic eh?
1 Kings 6:23-36; 7:27-39; 8:6-67 shows that Solomon's temple contained statues of cherubim as well as images of lions and oxen. Not once did God condemn the use of these statues and images in woship.
Col. 1:15 tells us that Jesus Christ is the only image of God that we worship. The Greek for "image" is "eikon" which tells the reader that we do worship only one image, and that is Jesus Christ. This image is different from a painting or a statue because Jesus Christ is real. Jesus is God in human form, and since it's God, we are right to worship Jesus. Catholics have never worshipped a statue or an image, and we will never do so.