diff --git a/src/less/lib/background.less b/src/less/lib/background.less
index 8d9221621..1f291a5fe 100644
--- a/src/less/lib/background.less
+++ b/src/less/lib/background.less
@@ -7,7 +7,7 @@
 @background-trans-color: "background/trans_normal.png";
 @background-trans-color-disabled: "background/trans_disable.png";
 @background-auto-color-square-normal: "icon/auto_square_normal.png";
-@background-auto-color-no-square-normal: "icon/auto_no_square_normal";
+@background-auto-color-no-square-normal: "icon/auto_no_square_normal.png";
 
 @background-farbtastic-wheel:"background/wheel.png";
 @background-farbtastic-overlay:"background/mask.png";