[silin]

можно просто менять bitmapData битмапа

var bmp:AimationBitmap = new AimationBitmap([new img1(0, 0), new img2(0, 0), new img3(0, 0)]);

public class AimationBitmap extends Bitmap
{
	private var _frames:Array/*BitmapData*/;
	private var _timer:Timer = new Timer(100);
	private var _currentFrame:int = 0;
	public function AimationBitmap(frames:Array/*BitmapData*/) 
	{
 
		super(frames[_currentFrame]);
		_frames = frames;
		_timer.addEventListener(TimerEvent.TIMER, onTimer);
		_timer.start();
	}
 
	private function onTimer(event:TimerEvent):void 
	{
		_currentFrame++;
		_currentFrame %= _frames.length;
		bitmapData = _frames[_currentFrame];
	}
 
}