How to set custom height and width for image loaded with loadClip

AS2 Experts,

I am new to flash. I have the following code that loads a png image into a MovieClip. When the image is rendered, it seems to me that the width and height is set to that of the png image. What I want is to be able to control the image width and height and set values specified in a different resource file. How would I do that. My intial tries to set the target._width and height is not helping.

var imageLoader:MovieClipLoader = new MovieClipLoader();
var listener:Object = new Object();
listener.owner = this;

	listener.onLoadInit = function(target:MovieClip) {
		trace ("******Inside onLoadInit: width/height " + target._width + " / " + 
                    target._height  ); 
			
		
	}


	imageLoader.addListener(listener);
	imageLoader.loadClip(source, target);