there are (at least, maybe there are even more I don't think of at the moment) several completely different things that the German word "Vorstellung" may denote. Which one is correct, depends on the context: a) introduction (of a person). doesn't fit here. b) imagination, impression, conception, idea, notion ... (this is what is needed here). c) show, screening, performance (countable): one particular show of a theatre play or film
I'll report it then. DL replaced my "opinion of him" with "vision of him", which I think sounds rather odd. Edited: I'm wrong. "Vision" comes closer than "opinion". There didn't appear to be a single English word to describe this particular use of the word of "Vorstellung“. One dictionary called it a mental image.
"That is not my view of him" was marked wrong. Looking at other posts in this thread, it seems to me that "meine Vorstellung" in this context is a very broad term, overlapping others like "Ansicht" or "Meinung", and that at the end of the day it could be translated in many different ways. It would be helpful to have more precise guidelines about what are and what are not acceptable translations.
"Eindruck" implies that you already met the person and now you have an idea how he is. It's not necessary that this idea matches the full reality of his character, but it matches the impression he made on you.
"Vorstellung" is entirely in your imagination. You may have heard or read about the person, but you never saw him, spoke to him, or have otherwise first hand experience with him. The picture your have is to an extend made out of your fantasy, wishes or fears based on whatever you learned about him. Once you meet him in person, you will correct your "Vorstellung" to an "Eindruck".