modify wordpress-ai-privacy plugin to generate gravatar url

wp-content/plugins/wordpress-ai-privacy-plugin/remove-gravatar.php

@@ -51,7 +51,7 @@ function get_avatar( $id_or_email, $size = '96', $default = '', $alt = false ) {
 
 
         if ( 'mystery' == $default )
-                $default = "http://noblogs.org/wp-content/plugins/buddypress/bp-core/images/mystery-man-50.jpg";
+                $default = plugins_url( 'images/mystery-man-50.jpg' , __FILE__ )
         elseif ( 'blank' == $default )
                 $default = includes_url('images/blank.gif');
                 $avatar = "<img alt='{$safe_alt}' src='{$default}' class='avatar' height='{$size}' width='{$size}' />";