diff --git a/api/common/Service/FileHandler.php b/api/common/Service/FileHandler.php
index 7041ed2..79ee9e7 100644
--- a/api/common/Service/FileHandler.php
+++ b/api/common/Service/FileHandler.php
@@ -42,7 +42,7 @@ class FileHandler {
         if ($file->getError() !== UPLOAD_ERR_OK) {
             return false;
         }
-        if (!in_array($file->getClientMediaType(), array_keys($this->valid_types))) {
+        if (!in_array($file->getClientMediaType(), $this->valid_types)) {
             return false;
         }
         if ($new_name === null) {