Re: Object size
Let's use a simple example. Imagine you are standing 1 foot directly in front of a mirror. How far away from you does the reflected image appear to you? Just look at the position of the feet. Your own feet are 1 foot away from the mirror, and the reflection of you appears 1 foot away from the mirror, so actually, the "distance" between your reflection and you is twice the distance between you and the mirror. So as you walk farther away from the mirror, your reflection does so as well, so the total distance between you and your reflection will always be twice the distance between you and the mirror itself. Therefore, if you walk very far away from the mirror, say 100 feet, then the reflection will appear to be 200 feet away, which will probably look like a small point in the mirror.
Of course, this is neglecting some math due to the fact that you are not a point particle and your eye level is roughly a point whereas your body is not. However, this assertion is approximately true.