Add Colorbox to a Nextgen Gallery

Question

I have a webshop with t-shirt products. For each t-shirt I have made a NextGen Gallery with the GalleryView (jQuery) template.

The problem is: I want to add a Colorbox to the big picture from the gallery, but I can't get it work...

This is the preview url: http://www.jaewhooclothing.com/collection/jae-whoo-limited-t-shirt-design/

I try to use this little script, but it is not working:

<script type="text/javascript">
$(document).ready(function() {
  $('.gv_panel img').colorbox({rel:'gal'});
});
</script>

Is there someone who know what I'm doing wrong here??