Custom Wordpress Gallery

functions.php

<?php

// DOWNLOAD GALLERY
function my_gallery_shortcode( $output, $attr ) {
 
    /* Custom gallery shortcode. */
    // 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'] );
    }
	
	global $post;
    extract(shortcode_atts(array(
            'order'      => 'ASC',
            'orderby'    => 'menu_order ID',
            'id'         => $post->ID,
            'itemtag'    => 'dl',
            'icontag'    => 'dt',
            'captiontag' => 'dd',
            'columns'    => 3,
            'size'       => 'thumbnail',
            'include'    => '',
            'exclude'    => '',
            'customgal'  => false
    ), $attr));
	
    if(!$attr['customgal']) return $output;
    // if($post->post_type != 'journalists') return $output;

    $id = intval($id);
    if ( 'RAND' == $order )
            $orderby = 'none';

    if ( !empty($include) ) {
            $include = preg_replace( '/[^0-9,]+/', '', $include );
            $_attachments = get_posts( array('include' => $include, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );

            $attachments = array();
            foreach ( $_attachments as $key => $val ) {
                    $attachments[$val->ID] = $_attachments[$key];
            }
    } elseif ( !empty($exclude) ) {
            $exclude = preg_replace( '/[^0-9,]+/', '', $exclude );
            $attachments = get_children( array('post_parent' => $id, 'exclude' => $exclude, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby) );
    } else {
            $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 $att_id => $attachment )
                    $output .= wp_get_attachment_link($att_id, $size, true) . "\n";
            return $output;
    }

    $itemtag = tag_escape($itemtag);
    $captiontag = tag_escape($captiontag);
    $columns = intval($columns);
    $itemwidth = $columns > 0 ? floor(100/$columns) : 100;
    $float = is_rtl() ? 'right' : 'left';

    $selector = "gallery-{$instance}";

    $gallery_style = $gallery_div = '';
    if ( apply_filters( 'use_default_gallery_style', true ) )
            $gallery_style = "
            <style type='text/css' media='screen'>
                    #{$selector} {
                            margin: auto;
                    }
                    #{$selector} .gallery-item {
                            float: {$float};
                            width: {$itemwidth}%;
                    }
                    #{$selector} img {
                            
                    }
                    #{$selector} .gallery-caption {
                            
                    }
            </style>
            <!-- see gallery_shortcode() in wp-includes/media.php -->";
    $size_class = sanitize_html_class( $size );
    $gallery_div = "<div id='$selector' class='download-gallery galleryid-{$id} gallery-columns-{$columns} gallery-size-{$size_class}'>";
    $output = apply_filters( 'gallery_style', $gallery_style . "\n\t\t" . $gallery_div );

    $i = 0;
    foreach ( $attachments as $id => $attachment ) {

            $link = isset($attr['link']) && 'file' == $attr['link'] ? wp_get_attachment_link($id, $size, false, false) : wp_get_attachment_link($id, $size, true, false);
         
             $thumbnail_image = wp_get_attachment_image_src( $id, 'thumbnail' );
             $large_image = wp_get_attachment_image_src( $id, 'large' );
             $fullsize_image = wp_get_attachment_image_src( $id, 'full-size' );
            
             $custom_div = "<div class='new-download-image'>
             	<a href='$large_image[0]' class='fancybox new-download-image-thumb' rel='fancybox-thumb-1'>
             		<img src='$thumbnail_image[0]' width='$thumbnail_image[1]' height='$thumbnail_image[2]' class='wp-image-$id' />
             	</a>
             	<div class='new-download-image-foot'>
             		<a href='$large_image[0]' class='fancybox' rel='fancybox-thumb-2'>Preview</a>
	             	<span>&#124;</span>
	             	<a href='$fullsize_image[0]' class='download-fullsize' target='_blank' title='Right click and Save target as...'>Download ($fullsize_image[1] x $fullsize_image[2])</a>	
             	</div>
             </div>";
           	
            $output .= "<{$itemtag} class='gallery-item'>";
            $output .= "
                    <{$icontag} class='gallery-icon'>
                            $custom_div
                    </{$icontag}>";
            if ( $captiontag && trim($attachment->post_excerpt) ) {
                    $output .= "
                            <{$captiontag} class='wp-caption-text gallery-caption'>
                            " . wptexturize($attachment->post_excerpt) . "
                            </{$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', 'my_gallery_shortcode', 10, 2 );

?>