Alpha fade AS 2.0

MovieClip.prototype.fadeIn = function(speed){
this.onEnterFrame = function(){
this._alpha+=speed;
if(this._alpha >= 100) delete this.onEnterFrame;
}
}
MovieClip.prototype.fadeOut = function(speed){
this.onEnterFrame = function(){
this._alpha-=speed;
if(this._alpha <= 0) delete this.onEnterFrame;
}
}

var pic_arr:Array = new Array("images/goldstein.png", "images/kyle.png", "images/timmy.png");
pic_arr.sort(function () {
    return random(2) ? true : false;
});
trace(pic_arr);
display();
function display() {
   player_mc.loadMovie(pic_arr[1]);
   player_mc.fadeIn(3);
   player_mc2.loadMovie(pic_arr[2]);
   player_mc2.fadeIn(3);
}
stop();

This code isnt working to fade in my loaded images. am i missing something?