Reflection from a Plane Mirror
The image distance always equals the object distance. The size of the image is the same as the object (the mirror does not magnify the image).
Reflection from a Concave Mirror
When the object is far from the mirror, the image is inverted and at the focal point. The image is real light rays actually focus at the image location). As the object moves towards the mirror the image location moves further away from the mirror and the image size grows (but the image is still inverted). When the object is that the focal point, the image is at infinity. As the object moves towards the mirror inside the focal point the image becomes virtual and upright behind the mirror. Initially the virtual image is much larger than the object and really far away, but as the object approaches the mirror the virtual image also approaches the mirror and decreases in size.
Reflection from Convex Mirror
The image produced by a convex mirror is always virtual, and located behind the mirror. When the object is far away from the mirror the image is upright and located at the focal point. As the object approaches the mirror the image also approaches the mirror and grows until its height equals that of the object.