There is most likely something to this. A dramatic example I've seen is where you take a picture of a head, and invert the mouth and view the picture upside down (so the head is pointing down, but the mouth is still right side up). It looks slightly off, but no more than any other picture that has been altered.

Now flip the picture back around right side up (mouth upside down) and if you aren't expecting it then it will quite likely make you jump back in horror. It actually hits some deeply rooted part of our primitive brain that just messes you up. (I just looked this up again, it is the Thatcher effect, and to me it is more frightening when the face is smiling).