function my_gallery_shortcode($attr) {
	global $post;
 
	static $instance = 0;
	$instance++;
 
	// Allow plugins/themes to override the default gallery template.
	$output = apply_filters('post_gallery', '', $attr);
	if ( $output != '' )
		return $output;
 
	// 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'    => 'div',
		'icontag'    => 'span',
		'captiontag' => 'p',
		'columns'    => 3,
		'size'       => 'full'
	), $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 $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;
 
	$selector = "gallery-{$instance}";
 
	$output = apply_filters('gallery_style', "
 
			#{$selector} {
				margin: auto;
			}
			#{$selector} .gallery-item {
				float: left;
				margin-top: 10px;
				text-align: center;
				width: {$itemwidth}%;			}
			#{$selector} img {
				border: 2px solid #cfcfcf;
			}
			#{$selector} .gallery-caption {
				margin-left: 0;
			}
 
		<!-- see gallery_shortcode() in wp-includes/media.php -->
		<div id="$selector" class="gallery galleryid-{$id}">");
 
	$i = 0;
	foreach ( $attachments as $id =&gt; $attachment ) {
		$link = isset($attr['link']) &amp;&amp; 'file' == $attr['link'] ? wp_get_attachment_link($id, $size, false, false) : wp_get_attachment_link($id, $size, true, false);
 
		$output .= "&lt;{$itemtag} class='gallery-item'&gt;";
		$output .= "
			&lt;{$icontag} class='gallery-icon'&gt;
				$link
			<!--{$icontag}-->";
		if ( $captiontag &amp;&amp; trim($attachment-&gt;post_excerpt) ) {
			$output .= "
				&lt;{$captiontag} class='gallery-caption'&gt;
				" . wptexturize($attachment-&gt;post_excerpt) . "
				<!--{$captiontag}-->";
		}
		$output .= "<!--{$itemtag}-->";
		if ( $columns &gt; 0 &amp;&amp; ++$i % $columns == 0 )
			$output .= '<br>';
	}
 
	$output .= "
 
		</div>\n";
 
	return $output;
}