how to make the window autosizeable according to diemsions of images being loaded??

<?page title="Auto Generated index.zul"?>
<div style="overflow:auto">
<window title="Hello World!!" border="normal" width="100%" height="100%" apply="test.vinhvo.Controller" id="win" >

<zk>

	<image src="img/myimg.jpg"></image>

</zk>
			
</window>
</div>