diff --git a/includes/server/actors.php b/includes/server/actors.php
index 82a1123..f4e5ebc 100644
--- a/includes/server/actors.php
+++ b/includes/server/actors.php
@@ -193,7 +193,7 @@ function get_user_actor( $user ) {
 }
 
 function make_icon_array( $icon_url ) {
-    $mime_type = wp_check_filetype( $icon_url );
+    $mime_type = wp_check_filetype( $icon_url )['type'];
     return array(
         'url' => $icon_url,
         'type' => 'Image',