diff --git a/src/Users/Assets/UserBackgroundAsset.php b/src/Users/Assets/UserBackgroundAsset.php
index 3af42c6..06cafe7 100644
--- a/src/Users/Assets/UserBackgroundAsset.php
+++ b/src/Users/Assets/UserBackgroundAsset.php
@@ -3,6 +3,7 @@ namespace Misuzu\Users\Assets;
 
 use InvalidArgumentException;
 use Misuzu\Config;
+use Misuzu\Config\CfgType;
 use Misuzu\Users\User;
 
 // attachment and attributes are to be stored in the same byte