There is not a template being used in that instance. The HTML is there after the template hook.
HTML Code:
<div><a href="album.php?' . $vbulletin->session->vars['sessionurl'] . 'u=' . $post['userid'] . '" rel="nofollow"><img src="images/buttons/add_album.png" border="0" alt="Member Photo Albums"></a></div>
You don't copy the entirety of the plugin in any case, as a template won't parse PHP. HTML inside of a plugin or PHP file will be specially formatted to prevent errors. You can tell what it is by the use of traditional HTML tags being used, such as the <div> tag in this case. You just need to strip out the PHP stuff, like the single quotes, the decimal points and spaces. Probably something like this:
HTML Code:
<div><a href="album.php?$session[sessionurl]u=$post['userid']" rel="nofollow"><img src="images/buttons/add_album.png" border="0" alt="Member Photo Albums"></a></div>
Note that I also changed the PHP variable to the kind that vB templates typically use.