Can't get height of image inside an mc

1

HI

I am trying to get at the properties (eg height) of an jpeg that I have loaded into a movieclip at runtime. Here’s the code


 
var introImageHolder:MovieClip = new MovieClip();
:
:
  var j =new Loader();
  j.load(new URLRequest(imgUrl));
  introImageHolder.addChild(j)
  introImageHolder.x=245;
  introImageHolder.y=108;

Sadly whilst the image loads correctly if I try
trace (introImageHolder.height) I get 0, which is odd - I would have thought that the mc would take on the size of its contents, but I guess I am missing something! Also trace (introImageHolder.j.height) throws errors

How do I get at the height of the image please?

Thanks

E