Question

The reason people seem to change size as they change sides in the ames room is that:

Answer 1

a lens in the peephole forces you to view them upside down.

Step-by-step explanation:

Answer 2

It's because the room is not actually rectangular
The Ames room is closer to a Trapezoid rather than rectangular.
So when the people change sides in the room, they actually got closer in distance from the people who see it from the front and give the impression that they're becoming larger.