diff --git a/plugins/windows-notification/src/wintoast.vala b/plugins/windows-notification/src/wintoast.vala
index 35e77f3d..050d8d73 100644
--- a/plugins/windows-notification/src/wintoast.vala
+++ b/plugins/windows-notification/src/wintoast.vala
@@ -40,7 +40,7 @@ namespace Dino.Plugins.WindowsNotification {
             }
         }
 
-        public bool show_message(string sender, string message, string image_path, int conv_id, void* class_obj, NotificationCallback callback) {
+        public bool show_message(string sender, string message, string? image_path, int conv_id, void* class_obj, NotificationCallback callback) {
             if (valid && library_show_message != null) {
                 return library_show_message(sender, message, image_path, conv_id, class_obj, callback) == 0;
             }