There is a great program called Morpher for doing image distortion. You can take one picture and "morph" this into a second picture. The most primititve way of doing this is to do a fade. That is, as you progress from one picture to the next each pixel slowly changes color from the color it is in the first image to the color it is in the last image. That's fine for a transition in a film, but the halfway shots aren't very interesting. Just a kind of half-there for each picture. Morphing is a little more than that.
The additional information you provide for Morpher is to identify points in the first picture to be associated with points in the second picture. For example, if you were morphing between my face and a llama, you might pick the center points of the eyes, the corners of the mouth, points along the hairline, and other visually important features. Unless the llama and I have a very similar face the distance between our eyes, for example, will be different. So, when a morph does a transition, in addition to the fade, it also does a distort. The distort is important for the halfway pictures. Essentially it moves each point you pick from the starting position to the ending position (and all the nearby points) across the duration of the morph. So, for example, at the halfway point, not only will the eyes be a color halfway between my eyes and the llama's eyes, but they will also be in a position halfway between where mine are and the llama's are. Cool, huh?
The upshot of all that is that as an image morphs, it seems to twist and distort from the original shape into second shape. This makes the halfway images very funny indeed. What would I look like as a half-Jo and half-Llama?
The last little trick this tool can do is a pure distort. This is the same as a morph, but without the fade. So, in the Jo to Llama example, when we finished the process, all of my bits would be in the position of a llama's, but they would still look like me. Too freaky.
What follows are a number of pictures I made with my friends. And I mean with my friends!
TANYA TO WILLOW
BUFFY TO TANYA
WHAT IF YOUR GIRLFRIEND LOOKED LIKE BARBIE?
WHAT IF BARBIE LOOKED LIKE YOUR GIRLFRIEND?