Не проверено, но вот суть:
var bitmaps:Array = [];
var tempClip = this.createEmptyMovieClip()
var timer;
function loadImage(){
timer = setInterval(checkHeight, 10)
var mc = tempClip.createEmptyMovieClip("img",this.getNextHighestDepth());
mc.loadMovie(myPathToMyImage)
}
function checkHeight(){
if (tempClip._height){
clearInterval(timer)
var bmp:BitmapData = new BitmapData(tempClip._width, tempClip._height, true);
bmp.draw(tempClip);
bitmaps.push(bmp);
tempClip.unloadMovie();
}
}