1. A graphic image system comprising: a source of a first signal representing a first image including a moving human subject having a head with a face; an image position estimating system for estimating the instantaneous position of said head of said human subject; a source of a second signal representing a second image including a character having a head with a mask outline; and means, responsive to said position estimating system and to said first and second signals, for dynamically defining an estimated boundary of said face of said human subject in said first image and for merging the face in said first image, as limited by said estimated boundary, with the second image within the mask outline.