Can't preview jQuery / Is my code wrong or is it just not previewing??

Can't preview jQuery / Is my code wrong or is it just not previewing??

Hello,

I am using jQuery in my html script in DreamWeaver. I think I coded it correctly, but whenever I preview whether it's in Firefox or in live view, I can't get it to work. What's supposed to happen is when I click an image with the class "menu_head," the rest of the navigation in the list classified as "menu_body" is supposed to appear. When I click, however, nothing happens. I don't know if I maybe sourced my javascript file wrong or what??

Here's my html code so far with the javascript.

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Amyris</title>
<link href="main.css" rel="stylesheet" type="text/css" />
<script src="jquery-1.9.1.min.js" type="text/javascript"></script>
<script type="text/javascript"> 
$(document).ready(function () {
    $("ul.menu_body li:even").addClass("alt");
});
$("img.menu_head").click(function () {
    $("ul.menu_body").slideToggle("medium");
});
</script>

</head>

<body>

<div id="wrapper">

<div id="nav"></div>

<img src="images/images/menu.png" width="183" height="42" class="menu_head" />

<ul class="menu_body"><br> 
  <li><a href="#">About Us</a></li><br> 
  <li><a href="#">Portfolio</a></li><br> 
 
  <li><a href="#">Clients</a></li><br> 
  <li><a href="#">Blog</a></li><br> 
  <li><a href="#">Support Forums</a></li><br> 
 
  <li><a href="#">Gallery</a></li><br> 
  <li><a href="#">Contact Us</a></li><br> 
</ul>
</div>

</body>

</html>