Subject:RE: Does My Helmet Fit My Head/Face Right?
I agree that it looks too small. You may also be wearing it a little tilted upward, but that may just be because it doesn't fit.
If it is sized correctly for you, you should be able to pull it down level (front and back), with the front midway on your forehand. Once tightened, it should stay there without your being able to slide it up or down.
Check out this site for sizing/fitting information: