source: trunk/www.guidonia.net/wp/wp-content/themes/carrington-mobile-1.0.2/carrington-core/attachment.php@ 44

<?php

// This file is part of the Carrington Theme Framework for WordPress
// http://carringtontheme.com
//
// Copyright (c) 2008-2009 Crowd Favorite, Ltd. All rights reserved.
// http://crowdfavorite.com
//
// Released under the GPL license
// http://www.opensource.org/licenses/gpl-license.php
//
// **********************************************************************
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
// **********************************************************************

function cfct_get_adjacent_image_link($prev = true) {
        global $post;
        $post = get_post($post);
        $attachments = array_values(get_children( array('post_parent' => $post->post_parent, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => 'ASC', 'orderby' => 'menu_order ID') ));

        foreach ( $attachments as $k => $attachment )
                if ( $attachment->ID == $post->ID )
                        break;

        $k = $prev ? $k - 1 : $k + 1;

        if ( isset($attachments[$k]) )
                return wp_get_attachment_link($attachments[$k]->ID, 'thumbnail', true);
}

function cfct_post_gallery($unused, $attr) {
        global $post;

        // We're trusting author input, so let's at least make sure it looks like a valid orderby statement
        if ( isset( $attr['orderby'] ) ) {
                $attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
                if ( !$attr['orderby'] )
                        unset( $attr['orderby'] );
        }

        extract(shortcode_atts(array(
                'order'      => 'ASC',
                'orderby'    => 'menu_order ID',
                'id'         => $post->ID,
                'itemtag'    => 'dl',
                'icontag'    => 'dt',
                'captiontag' => 'dd',
                'columns'    => 3,
                'size'       => 'thumbnail'
        ), $attr));

        $id = intval($id);
        $attachments = get_children( array('post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );

        if ( empty($attachments) )
                return '';

        if ( is_feed() ) {
                $output = "\n";
                foreach ( $attachments as $id => $attachment )
                        $output .= wp_get_attachment_link($id, $size, true) . "\n";
                return $output;
        }

        $itemtag = tag_escape($itemtag);
        $captiontag = tag_escape($captiontag);
        $columns = apply_filters('cfct_post_gallery_columns', intval($columns));
        $itemwidth = $columns > 0 ? floor(100/$columns) : 100;

        $output = apply_filters('gallery_style', "
                <style type='text/css'>
                        .gallery {
                                margin: auto;
                        }
                        .gallery-item {
                                float: left;
                                margin-top: 10px;
                                text-align: center;
                                width: {$itemwidth}%;                   }
                        .gallery img {
                                border: 2px solid #cfcfcf;
                        }
                        .gallery-caption {
                                margin-left: 0;
                        }
                </style>
                <!-- see cfct_post_gallery() in carrington-core/attachment.php -->
                <div class='gallery'>");

        $i = 0;
        foreach ( $attachments as $id => $attachment ) {
// get full item src
                $item_src = wp_get_attachment_image_src($id, 'full', false);

                $link = isset($attr['link']) && 'file' == $attr['link'] ? wp_get_attachment_link($id, $size, false, false) : wp_get_attachment_link($id, $size, true, false);
                
// add full item src as rel
                $link = str_replace('><img', ' class="thickbox" rel="'.$item_src[0].'"><img', $link);

                $output .= "<{$itemtag} class='gallery-item'>";
                $output .= "
                        <{$icontag} class='gallery-icon'>
                                $link
                        </{$icontag}>";
                if ( $captiontag && trim($attachment->post_excerpt) ) {
                        $output .= "
                                <{$captiontag} class='gallery-caption'>
                                {$attachment->post_excerpt}
                                </{$captiontag}>";
                }
                $output .= "</{$itemtag}>";
                if ( $columns > 0 && ++$i % $columns == 0 )
                        $output .= '<br style="clear: both" />';
        }

        $output .= "
                        <br style='clear: both;' />
                </div>\n";

        return $output;
}
add_filter('post_gallery', 'cfct_post_gallery', 10, 2);

?>