.css not changing background image on mouseover!

.css not changing background image on mouseover!

Here's my code (it is fired, and does find the object, but won't change the background image): But it's not the image that's the problme, because even trying to change the background-color doesn't work either.

[code]
<div id="myDiv">
     <div class="mySubDiv"><img class="icon" /></div>
</div>
       
<script type="text/javascript">
       $( "#myDiv" ).mouseover(
           function(mouseEvent)
           {
               $( "#myDiv" ).children( ".icon" ).css( "background-image", "url('../images/icon_pressed.png')" );

               //This also does not work
               $( "#myDiv" ).children( ".icon" ).css( "visibility", "hidden" );
           }
       );
</script>
[/code]

What am I doing wrong?