Target top LI level individually

Target top LI level individually

Hi Guys,

Am having a fiddle with the following for a while now and am not getting anywhere - also not knowing if what i am trying is actually the best / fastest way...

What i have is the following menu
--------------------------------
<ul>
<li>Test</li>
<li>Test
     <ul>
     <li>Test</li>
     <li>Test</li>
     <li>Test</li>
     </ul>
     </li>
<li>Test</li>
<li>Test</li>
</ul>
--------------------------------

In the head i have 'tried' the following

--------------------------------
<script type="text/JavaScript">
$(function(){
$("ul li a:nth-child(1)").prepend("<img src=""test1.png""/>");
$("ul li a:nth-child(2)").prepend("<img src=""test2.png""/>");
$("ul li a:nth-child(3)").prepend("<img src=""test3.png""/>");
$("ul li a:nth-child(4)").prepend("<img src=""test4.png""/>");
});
</script>
--------------------------------

This will of course not work as nth-child selects 'all' childs, but i have no idea how to target the first set of LI's individually.
Can anyone point me in the right direction for this?

Big big thank you in advance!