diff --git a/src/Contracts/CollageGenerator.php b/src/Contracts/CollageGenerator.php
index aa61965..bd9ef15 100644
--- a/src/Contracts/CollageGenerator.php
+++ b/src/Contracts/CollageGenerator.php
@@ -47,6 +47,7 @@ abstract public function create($closure = null);
      */
     protected function transformFiles()
     {
+        /** @var \Illuminate\Support\Collection<int, Image> $images */
         $images = collect();
         foreach ($this->file->getFiles() as $file) {
             if ($file instanceof Image) {