diff --git a/doc/Using-vipsthumbnail.xml b/doc/Using-vipsthumbnail.xml
index a195f4ba..4d51cf56 100644
--- a/doc/Using-vipsthumbnail.xml
+++ b/doc/Using-vipsthumbnail.xml
@@ -16,8 +16,8 @@
The thumbnailing functionality is implemented by vips_thumbnail() and vips_thumbnail_buffer() (which thumbnails an image held as a string), see the docs for details. You can use these functions from any language with a libvips binding. For example, from PHP you could write:
-
-$filename = ...;
+
+$filename = "image.jpg";
$image = Vips\Image::thumbnail($filename, 200, ["height" => 200]);
$image->writeToFile("my-thumbnail.jpg");