I guess it is because of preception.... if your standing about a metre away from the mirror... it will appear your reflection is a metre behind the mirror
It's a virtual reflection of the object which appears as an image as much behind the mirror as the distance of the object in front.
A concave mirror will focus an image and make it appear smaller. A convex mirror will disperse an image and make it appear larger.
Convex
The image location is where the observer is sighting when viewing the image.
behind you
Same distance behind mirror.
It's a virtual reflection of the object which appears as an image as much behind the mirror as the distance of the object in front.
The same speed: the image will always appear to be at a point exactly behind the mirror as the object is in front.
Since the mirror reflects the image in front of it, the apparent distance of oneself standing in the mirror will be twice as far as the distance from you to the mirror. If you are standing 2 meters from the mirror, the image will appear as 4 meters away.
A concave mirror will focus an image and make it appear smaller. A convex mirror will disperse an image and make it appear larger.
behind the mirror. The object appears to be behind the mirror
Your question isn't really clear. In one interpretation - you don't get an image behind a good mirror, as good mirrors aren't transparent. As close to all light that hits the front of the mirror as to make no difference will be bounced back the way it came. Now, if you have a poor mirror, some light will actually continue through, and the image visible behind the mirror would be as if there was a window instead of a mirror - only a lot weaker.
Convex
inside a mirror
The light from an object falls on the mirror. If these rays were to be extended backwards then they would meet behind the mirror making the image also at the back of the mirror. We can't catch this image on the screen. The image looks smaller due to one of the laws of depth perception. This makes the image look even smaller.
The image location is where the observer is sighting when viewing the image.
behind you