An idea for improving swapping differing face sizes
Was reading this post - viewtopic.php?f=27&t=1647 - of someone trying to replace a large face with a smaller face and it got me thinking, more believable swaps could probably be made if a 'heal' pass (take some of the surrounding background around a face and drawn inward) was run over the old face prior to drawing in the new face.
Here is an example of heal being run on GIMP to remove a chicken from a photo - .
Heal isn't perfect but it should look much better than the grey background produced when a smaller face is replacing a larger face.