Fancybox works with some photos and not others

Fancybox works with some photos and not others

I have a site in which fancybox is installed.
http://development-server-one.com/
In the gallery section the first couple pictures work as intended and the
fifth works, however every other picture does not function with Fancybox.
I have looked for this specific solution on these forums to no avail. If
someone knows of a post that addresses this issue I would greatly
appreciate a link. My looks like this:
<link rel="stylesheet" type="text/css"
href="includes/fancy/source/jquery.fancybox.css">
<link rel="stylesheet" type="text/css" href="includes/ks_gallery.css">
<link rel="stylesheet" type="text/css" href="includes/kc.css">
<link rel="stylesheet" href="includes/font_cal/stylesheet.css"
type="text/css" charset="utf-8" />
<script type="text/javascript"
src="includes/fancy/lib/jquery-1.10.1.min.js"></script>
<script type="text/javascript"
src="includes/fancy/source/jquery.fancybox.pack.js"></script>
<script type="text/javascript"
src="includes/jquery.imgpreload-master/jquery.imgpreload.min.js"></script>
<script type="text/javascript" src="includes/kc.js"></script>
<script type="text/javascript" src="includes/ks_gallery.js"></script>
And the links to the images look like:
<a class="thumbnail" title="This is a test caption"
href="imgs/k/cat_test.jpg" data-keywords="misc"><img
src="imgs/k/cat_t.png" /></a>
I have added the fancybox class via a .js file and have "rel=grouped" them
in the same way.
Any insight or a link to more information would be greatly appreciated.