It’s not a standard expression, if that’s what you mean. If I remember correctly, that sentence got a rating of 恥ずかしい台詞禁止.
That being said, it’s not weirder than “the mind’s eye” and so on. (I’m not saying they are the same thing, though).
The image in your heart, for me, would be your internal representation of the world. Anything you experience would live a mark, I guess, but reflection means that it really mirror the thing you heard/saw, i.e. you were so affected it became a part of you and how you see the world. (Which allows that image to persist, since you will also affect others in turn)
5 Likes
Maybe we should be saying 恥ずかしいセリフ禁止 to you! 
Thanks! 
3 Likes
Interestingly, when I was thinking about how to put it into English, “the mind’s eye” was the first thing that came to my mind!
1 Like
Yes, I may not completely understand what that expression means. I thought it was about how you interpret the world (I.e. turn sensory inputs into meaning), but I guess I was wrong 