diff --git a/tools/opticharger b/tools/opticharger
index a3d7ade..0473008 100755
--- a/tools/opticharger
+++ b/tools/opticharger
@@ -45,7 +45,7 @@
 then
     optimize_png () {
         pngcrush -q ${BRUTECRUSH} $1 ${1}.out 1> /dev/null 2> /dev/null
-        mv ${1}.out ${1}
+        mv ${1}.out ${1} 2> /dev/null
     }
 elif [ "$(which optipng)" != "" ];
 then