Mirrors can be separated into three basic categories, all of which reflect light and images in different ways. An image in a mirror may appear to be larger, smaller, closer or more distant than it really is. The reflection of that image may also be a virtual image, reversed or upside down. The three primary types of mirrors are plane, concave and convex.
A plane mirror is flat, reflecting light rays in the order they are received. The image seen in a plane mirror will appear to be backward, as it is reversed left to right. An object's size and distance will be the same in a plane-mirror reflection as it is in reality.
The light rays that strike a concave mirror come together at a fixed point. The hallmark of this type of mirror is that the reflective surface resembles the interior of a bowl, bending inward. A concave mirror is thicker at its edges than at its center, and produces images that appear larger than they are in reality.
The reflective surface of a convex mirror bends out, like the exterior profile of a bowl. Objects seem smaller than they really are when reflected in convex mirrors. They will appear to be upright if the mirror is held very close to a person's eyes. Move the mirror a few feet away and the object will be inverted. A convex mirror is thicker at its center than at its edges.