(XML slideshow) Scaling problem

programming flash
1

I am using the XML slideshow file from kirupa.
http://www.kirupa.com/developer/mx2004/xml_slideshow.htm
I basically didn’t change anything in the file yet, now i want to make the images be scaleable to the screen size. The imagecontainer in the file has a instance name called picture. Now i made the background scale allready and now i want the image to do something the same as the background but when i add the script the image disappears.
Does somebody know what i am doing wrong in the script ?
for now i only tested the screen width scaling.
Can somebody please help me out ???

Stage.align = "TL";
Stage.scaleMode = "noScale";
stop ();

background._x = 7;
background._y = 7;
ratio = background._width/background._height;
background._width = Stage.width-14;
background._height = (background._width/ratio);
picture._width = Stage.width;

sizeListener = new Object();
sizeListener.onResize = function() {
    background._x = 7;
    background._y = 7;
    ratio = background._width/background._height;
    background._width = Stage.width-14;
    background._height = (background._width/ratio);
    picture._width = Stage.width;
};