diff --git a/src/Lightbox.php b/src/Lightbox.php
index 93f2c03..ab0236b 100644
--- a/src/Lightbox.php
+++ b/src/Lightbox.php
@@ -7,6 +7,9 @@
 
 class Lightbox extends Widget {
 
+    /**
+     * @var array containing the attributes for the images
+     */
     public $files = [];
 
     public function init() {
@@ -15,19 +18,26 @@ public function init() {
 
     public function run() {
         $html = '';
-        foreach($this->files as $file) {
-            if(!isset($file['thumb']) || !isset($file['original'])) {
+        foreach ($this->files as $file) {
+            if (!isset($file['thumb']) || !isset($file['original'])) {
                 continue;
             }
 
-            $img = Html::img($file['thumb']);
-            $a = Html::a($img, $file['original'], [
-                'data-lightbox' => 'image-' . uniqid(),
+            $attributes = [
                 'data-title' => isset($file['title']) ? $file['title'] : '',
-            ]);
+            ];
+
+            if (isset($file['group'])) {
+                $attributes['data-lightbox'] = $file['group'];
+            } else {
+                $attributes['data-lightbox'] = 'image-' . uniqid();
+            }
+
+            $img = Html::img($file['thumb']);
+            $a = Html::a($img, $file['original'], $attributes);
             $html .= $a;
         }
         return $html;
     }
 
-}
+}
\ No newline at end of file