var mousePoint:Point = new Point(this.stage.mouseX, this.stage.mouseY);
mousePoint = globalToLocal(mousePoint);//還有localToGlobal
this.bigimg.x = mousePoint.x;
this.bigimg.y = mousePoint.y;
mousePoint = globalToLocal(mousePoint);//還有localToGlobal
this.bigimg.x = mousePoint.x;
this.bigimg.y = mousePoint.y;