Take your average blogger. This one below is a typical example of the species and will serve nicely as a subject for this experiment
Now get him to look serious and brooding into the camera for a moment. You might want to tell him that Farscape was never as good as Star Trek, or that Facebook is only MySpace for snobs, or some such thing.
Then crop the image close, only only allowing half the face to show, as this will remove any sense of an asymmertrical skull structure and the viewer will automatically assume the rest of the face to be well balanced.
Desaturate the image as Black & White photography gives a sense of artistic and cultural superiority. Now boost the contrast on the iris to make it stand out more.
Finally, darken the background and fine tune the brightness and contrast on the rest of the face, making the lights lighter and the darks darker.
Et Voilà, you now have the photo for the dust cover of the Blogger's next best selling hardback.
Of course it would help if he ever got round to writing it.