Here's the logic response to Peter's experimenting:

[UPDATE] Since I've gotten some favorable response to this post, both in the comments and in email, I thought I would give some special, behind-the-scenes information

When I saw Peter's pictures, I immediately thought of the series (1,2) of photoshop trickery I did a while back. Look familiar?

Now, if you'll notice, in Peter's original, he is looking straight at the camera.  So, I had to fix the eyes and distort the nose so he's looking over at Jenkies, who is also obviously added to the scene.