The three original heads are top left, centre, and bottom right. The rest are tweened and age-tweeked extrapolations, courtesy of FaceGen.
You should be able to get much better results than this with a more representative set of photos. A more useful source picture taken between the "Jackson Five" years and "Thriller", would have been handy, but the otherwise-usable ones that I turned up on the net all seemed to be in monochrome. :(
"Bottom left" is what FaceGen extrapolates for Michael Jackson as a fifty-something-yearold with no plastic surgery, top right runs the process in reverse, working backwards from the last picture. The rest are intermediates.