Here is an interesting science article from the New York Times. I've been reading a lot lately about how mirrors can help psychological disorders that no medications can help-- like getting rid of phantom limbs or phantom pains in amputees.
The main point of the article is to explain the fact that, when you look in a mirror, no matter how far you are from the mirror, your image on the mirror's surface will remain the same size. This is due to the fact that the mirror is always half-way between you and your reflected image.
There are other interesting things in the article: there is research that people are more self-aware when mirrors are around. If you are in a room with a mirror, you are less likely to cheat or judge people and more likely to help others.
On a separate note, the article says that when people are presented with photos of themselves which are airbrushed to look better, worse, or left the same, people identify the best photograph as the one untouched. But they only did that with their own photos-- for other people's photos they could identify the unairbrushed image.