What I try to do is displaying one bigger image and some additional smaller images below which should be shown in the bigger image div on hover.
I got this far but how do make the bigger div display its default content when none of the thumbnails is hovered?
HTML Structure:
<div class="preview">
    <img src="...">
</div
<div class="thumbs">
    <img src="..." class="zoom" rel="...">
    <img src="..." class="zoom" rel="...">
</div>
jQuery:
$(function(){
  $("img.zoom").mouseover(
    function(){
      $(".preview").html( $("<img>").attr("src", $(this).attr("rel")) );
    }
  );
});