I think there’s no need to use a plugin in this case. A manual approach should avoid problems with updates of WP and/or other plugins.
To use pretty photo library without a plugin just link css and js files in your header.php
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_directory'); ?>/prettyPhoto.css" /><br />
<script src="<?php bloginfo('stylesheet_directory'); ?>/js/jquery.prettyPhoto.js" type="text/javascript"></script><br />
or use a hook in your functions.php and load these files only where needed (i.e.: if (is_single() | is_page() | is_archive() ) -> load PP ).
Then add the lines below to jquery.prettyPhoto.js or to a new js file that you have to include as well:
jQuery.noConflict();
jQuery(document).ready(function() {
var items = jQuery('a').filter(function() {
return jQuery(this).attr('href').match(/\.(jpg|png|gif)/);
});
if (items.length > 1){
var gallerySwitch="[alltogethernow]";
}else{
var gallerySwitch="";
}
items.attr('rel','zoom'+gallerySwitch);
jQuery("a[rel^='zoom']").prettyPhoto();
});
It simply checks for every <a>
tag linking an image and adds the correct rel to it, making a single photo zoom or a gallery.