Yes he is Gods image. An image is NEVER the real thing.
You aren't interpreting the entire verse, the two ideas are connected. The Son is the image of the Father, if you see Him you see the Father. The Son is the "face of God" that side of God turned to man in self-revelation:
9 Jesus said to him, "Have I been with you so long, and yet you have not known Me, Philip?
He who has seen Me has seen the Father; so how can you say,`Show us the Father '?
10
"Do you not believe that I am in the Father, and the Father in Me? The words that I speak to you I do not speak on My own authority; but the Father who dwells in Me does the works.
11 "Believe Me that
I am in the Father and the Father in Me, or else believe Me for the sake of the works themselves.
(Jn. 14:9-11 NKJ)
For it is the
God who commanded light to shine out of darkness, who has shone in our hearts
to give the light of the knowledge of the glory of God in the face of Jesus Christ. (2 Cor. 4:6 NKJ)
Jesus is the Word of God, that is, He is the verbalization of God's thought:
In the beginning was the Word, and the Word was with God, and the
Word was God.
2 He was in the beginning with God.
3
All things were made through Him, and without Him nothing was made that was made. (Jn. 1:1-3 NKJ)
In other words, the thought of God is made concrete real, by the Word, He is its verbalized form.
By the word of the LORD the heavens were made, And all the host of them
by the breath of His mouth. (Ps. 33:6 NKJ)
All creation exists in the infinite Mind of God, it is God the Word Jesus Christ who gives it concrete reality, in Him all things consist and have their being:
15
He is the image of the invisible God, the firstborn over all creation.
16
For by Him all things were created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions or principalities or powers. All things were created through Him and for Him.
17 And He is before all things,
and in Him all things consist. (Col. 1:15-17 NKJ)
In that sense Jesus is "Firstborn" over all creation, He is its heir, He has pre-eminence.
Just as Ephraim is called firstborn (Jer. 31:9) even though Manasseh was first born, it does not refer to "origin". It refers to preeminence, the kind only God has over His creation.
Paul is linking the two thoughts, while you are separating "firstborn" from His being the image of God, and Paul in context then explains he is talking about how
Christ makes the Father real, give us a picture of "the invisible God" that we can see.
The Word of God as the face of God that is turned towards us to communicate and make Himself known, is one of the first things the Bible reveals:
8 And they heard
the voice of the LORD God walking in the garden in the cool of the day: and Adam and his wife hid themselves from the presence of the LORD God amongst the trees of the garden.
9 And the LORD God called unto Adam, and said unto him, Where art thou? (Gen. 3:8-9 KJV)
The Watchtower has completely missed Paul's point he clearly made right in the context. Christ makes the invisible God visible, He is the image we see and can know the Father by knowing Him. He is preeminent over all creation, IN HIM ALL THINGS COHERE, HOLD TOGETHER, CONSIST. Jesus makes God's thought concrete real, He brings God's Thought into actuality verbalizing it. He is the Word of God.