diff --git a/inc/bootstrap-wp-gallery.php b/inc/bootstrap-wp-gallery.php
index 6ccc70c..1a471a2 100644
--- a/inc/bootstrap-wp-gallery.php
+++ b/inc/bootstrap-wp-gallery.php
@@ -1,105 +1,129 @@
 <?php
-//Based on Roots Sage Gallery: https://github.com/roots/sage/blob/5b9786b8ceecfe717db55666efe5bcf0c9e1801c/lib/gallery.php
+//Based on Jeff Hays code and his article here: http://robido.com/wordpress/wordpress-gallery-filter-to-modify-the-html-output-of-the-default-gallery-shortcode-and-style/
+// Custom filter function to modify default gallery shortcode output
+function bootstrap_wp_gallery( $output, $attr ) {
 
-// Remove built in shortcode
-remove_shortcode('gallery', 'gallery_shortcode');
 
-// Replace with custom shortcode
-function shortcode_gallery($attr) {
-  $post = get_post();
+  // Initialize
+  global $post, $wp_locale;
+
+  // Gallery instance counter
   static $instance = 0;
   $instance++;
-  if (!empty($attr['ids'])) {
-    if (empty($attr['orderby'])) {
-      $attr['orderby'] = 'post__in';
-    }
-    $attr['include'] = $attr['ids'];
+
+  // Validate the author's orderby attribute
+  if ( isset( $attr['orderby'] ) ) {
+    $attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
+    if ( ! $attr['orderby'] ) unset( $attr['orderby'] );
   }
-  $output = apply_filters('post_gallery', '', $attr);
-  if ($output != '') {
-    return $output;
-  }
-  if (isset($attr['orderby'])) {
-    $attr['orderby'] = sanitize_sql_orderby($attr['orderby']);
-    if (!$attr['orderby']) {
-      unset($attr['orderby']);
-    }
-  }
-  extract(shortcode_atts([
+
+  // Get attributes from shortcode
+  extract( shortcode_atts( array(
     'order'      => 'ASC',
     'orderby'    => 'menu_order ID',
     'id'         => $post->ID,
-    'itemtag'    => '',
-    'icontag'    => '',
-    'captiontag' => '',
+    'itemtag'    => 'div',
+    'icontag'    => 'div',
+    'captiontag' => 'div',
     'columns'    => 3,
     'size'       => 'thumbnail',
-    'include'    => '',
-    'exclude'    => '',
-    'link'       => ''
-  ], $attr));
-  $id = intval($id);
-  $columns = (12 % $columns == 0) ? $columns : 3;
-  $grid = sprintf('col-sm-%1$s col-lg-%1$s', 12 / $columns);
-  if ($order === 'RAND') {
-    $orderby = 'none';
-  }
-  if (!empty($include)) {
-    $_attachments = get_posts(['include' => $include, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby]);
-    $attachments = [];
-    foreach ($_attachments as $key => $val) {
-      $attachments[$val->ID] = $_attachments[$key];
+    'exclude'    => ''
+  ), $attr ) );
+
+  // Initialize
+  $id = intval( $id );
+  $attachments = array();
+  if ( $order == 'RAND' ) $orderby = 'none';
+
+
+  if ( ! empty( $include ) ) {
+
+    // Include attribute is present
+    $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 ) );
+
+    // Setup attachments array
+    foreach ( $_attachments as $key => $val ) {
+      $attachments[ $val->ID ] = $_attachments[ $key ];
     }
-  } elseif (!empty($exclude)) {
-    $attachments = get_children(['post_parent' => $id, 'exclude' => $exclude, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby]);
+
+  } else if ( ! empty( $exclude ) ) {
+
+    // Exclude attribute is present
+    $exclude = preg_replace( '/[^0-9,]+/', '', $exclude );
+
+    // Setup attachments array
+    $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(['post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby]);
+    // Setup attachments array
+    $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()) {
+
+  if ( empty( $attachments ) ) return '';
+
+  // Filter gallery differently for feeds
+  if ( is_feed() ) {
     $output = "\n";
-    foreach ($attachments as $att_id => $attachment) {
-      $output .= wp_get_attachment_link($att_id, $size, true) . "\n";
-    }
+    foreach ( $attachments as $att_id => $attachment ) $output .= wp_get_attachment_link( $att_id, $size, true ) . "\n";
     return $output;
   }
-  $unique = (get_query_var('page')) ? $instance . '-p' . get_query_var('page') : $instance;
-  $output = '<div class="gallery gallery-' . $id . '-' . $unique . '">';
-  $i = 0;
-  foreach ($attachments as $id => $attachment) {
-    switch($link) {
-      case 'file':
-        $image = wp_get_attachment_link($id, $size, false, false);
-        break;
-      case 'none':
-        $image = wp_get_attachment_image($id, $size, false, ['class' => 'thumbnail img-thumbnail']);
-        break;
-      default:
-        $image = wp_get_attachment_link($id, $size, true, false);
-        break;
-    }
-    $output .= ($i % $columns == 0) ? '<div class="row gallery-row">' : '';
-    $output .= '<div class="' . $grid .'">' . $image;
-    if (trim($attachment->post_excerpt)) {
-      $output .= '<div class="caption hidden">' . wptexturize($attachment->post_excerpt) . '</div>';
-    }
-    $output .= '</div>';
-    $i++;
-    $output .= ($i % $columns == 0) ? '</div>' : '';
-  }
-  $output .= ($i % $columns != 0 ) ? '</div>' : '';
-  $output .= '</div>';
-  return $output;
-}
-add_shortcode('gallery', 'shortcode_gallery');
 
-/**
- * Add class="thumbnail img-thumbnail" to attachment items
- */
-function attachment_link_class($html) {
-  $html = str_replace('<a', '<a class="thumbnail img-thumbnail"', $html);
-  return $html;
+  // Filter tags and attributes
+  $itemtag = tag_escape( $itemtag );
+  $captiontag = tag_escape( $captiontag );
+  $columns = intval( $columns );
+  $itemwidth = $columns > 0 ? floor( 12 / $columns ) : 100;
+  $float = is_rtl() ? 'right' : 'left';
+  $selector = "gallery-{$instance}";
+
+ // Filter gallery CSS
+  $output = apply_filters( 'gallery_style', "
+
+    <div class='gallery galleryid-{$id} row'  id='$selector'>"
+  );
+
+  // Iterate through the attachments in this gallery instance
+  $i = 0;
+  foreach ( $attachments as $id => $attachment ) {
+
+    // Attachment link
+    $link = isset( $attr['link'] ) && 'file' == $attr['link'] ? wp_get_attachment_link( $id, $size, false, false ) : wp_get_attachment_link( $id, $size, true, false );
+
+    // Start itemtag
+    $output .= "<{$itemtag} class='gallery-item col-md-{$itemwidth}'>";
+
+    // icontag
+    $output .= "
+    <{$icontag} class='gallery-icon'>
+      $link
+    </{$icontag}>";
+
+    if ( $captiontag && trim( $attachment->post_excerpt ) ) {
+
+      // captiontag
+      $output .= "
+      <{$captiontag} class='gallery-caption'>
+        " . wptexturize($attachment->post_excerpt) . "
+      </{$captiontag}>";
+
+    }
+
+    // End itemtag
+    $output .= "</{$itemtag}>";
+
+    // Line breaks by columns set
+    if($columns > 0 && ++$i % $columns == 0) $output .= '<br style="clear: both">';
+
+  }
+
+  // End gallery output
+  $output .= "
+    <br style='clear: both;'>
+  </div>\n";
+
+  return $output;
+
 }
-add_filter('wp_get_attachment_link', 'attachment_link_class', 10, 1);
+
+// Apply filter to default gallery shortcode
+add_filter( 'post_gallery', 'bootstrap_wp_gallery', 10, 2 );