Why do people in the mirror of clothing stores look thinner?

1, the problem of mirroring. There are some ups and downs on the surface of the mirror, which refracts light early, and finally the light that enters the eyes changes from a straight line to a curve, so it looks very thin, which is what the folks call a haha mirror!

2, placement problems, some merchants put the mirror on the ground, but it is not straight, a little oblique, making people look tall and thin. This is the same as looking up on stage.