A Christian that believe in one God and gives him no image. What kind of Christian is that? I always believed in One God, with no image( which for me means no mental image of something). 
Jesus Christ is a prophet from God. I was taught in this way. I was in a Catholic College and I never heard from a priest that Jesus Christ is God. What type of Christian am I? 

I ask this because many non-Christians tend to believe that all Christians believe that the son of Mary is God - I'm not talking about trinity here because as I said, I believe in One God.
Virtually all Christians consider Jesus to be the image of God because of this passage in Colossians 1:15-16


  The Son is the image of the invisible God, the firstborn over all creation. For in him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through him and for him. 


If you are concerned with the question of whether Jesus is actually God, rather than whether he is merely the image of God, then the word you are looking for is probably 'Unitarian'. Unitarians believe that Jesus is the best and ultimate prophet and messenger of God, but not actually God. There are other kinds of groups too, including 'Christadelphians'. If you want more specific information you would have to tell us more about what you believe. Unitarians and Christadelphians consider Jesus to be the image of God, for the reasons I said above.

If your Catholic priest never said at any time that Jesus Christ is God, then he either presumed you already knew that or, if you were of a different faith, didn't want to offend you by contradicting your faith. He almost certainly believed it himself.