My friend bought two normal mirrors from some shop probably IKEA, looking like this one:

My images are different from the two. One is a little fatter and shorter, and the other a little thinner and taller. I wonder what can possibly be the reasons?
- They basically look the same, smooth and flat surfaces, almost the same size (one has a label saying 37x134cm), except one having a little thicker decoration border than the other. The one with thinker edge is the one giving me fatter and shorter image.
- I don't have other things to place them, so I just make both of them stand on the floor, with a small angle lying against the wall. Although the two mirrors are placed in the same way, will different placement of the mirrors change my image?
- What kinds of mirrors (size, ...) and how to place them will give me more realistic image of myself?