diff --git a/images/default-group-mm.jpg.png b/images/default-group-mm.png
similarity index 100%
rename from images/default-group-mm.jpg.png
rename to images/default-group-mm.png
diff --git a/mod/acl.php b/mod/acl.php
index 352c487195..cb5959a95b 100644
--- a/mod/acl.php
+++ b/mod/acl.php
@@ -50,7 +50,7 @@ function acl_init(&$a){
 	foreach($r as $g){
 		$groups[] = array(
 			"type"  => "g",
-			"photo" => "images/default-group-mm.jpg",
+			"photo" => "images/default-group-mm.png",
 			"name"  => $g['name'],
 			"id"	=> intval($g['id']),
 			"uids"  => array_map("intval", explode(",",$g['uids']))