diff --git a/io-webp.c b/io-webp.c
index 0c1532a..af24189 100644
--- a/io-webp.c
+++ b/io-webp.c
@@ -204,6 +204,18 @@ write_array (const uint8_t *data, size_t data_size, const WebPPicture *const pic
   return TRUE;
 }
 
+static gboolean
+is_save_option_supported (const gchar *option_key)
+{
+  char *options[3] = { "quality", "preset", NULL };
+  for (char **o = options; *o; o++)
+    {
+      if (g_strcmp0 (*o, option_key) == 0)
+        return TRUE;
+    }
+  return FALSE;
+}
+
 static gboolean
 save_webp (GdkPixbuf        *pixbuf,
            gchar           **keys,
@@ -375,6 +387,8 @@ fill_vtable (GdkPixbufModule *module)
 
   module->save             = save;
   module->save_to_callback = save_to_callback;
+
+  module->is_save_option_supported = is_save_option_supported;
 }
 
 G_MODULE_EXPORT void