Adding a Bitmap file

programming flash
1

Hi,

I have this AS3

var buttonWidth:Number = 60;
    var background:Shape = new Shape();
    background.graphics.beginFill(0x333333);
 background.graphics.lineStyle(1, 0xffffff);
    background.graphics.drawRect(20, -10, buttonWidth, 30);

How can I swap this for a png file??

Thanks
Phil