[]动态加载的图片不响应按钮点击事件

var imgURL:URLRequest = new URLRequest();
imgURL.url="res/data/image/522.png";
var imgLoader:Loader = new Loader();
imgLoader.load(imgURL);
imgLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, finished);
function finished(evt:Event):void {
var img:Bitmap = new Bitmap(evt.target.content.bitmapData);
stage.addChild(img);
img.x=100;
img.y = 100;
img.addEventListener(function() {
trace("QQQQQQQQ")
})
}
想给Img设置size 不过没有这个属性，求帮助