diff --git a/docs/handbook/image-file-formats.rst b/docs/handbook/image-file-formats.rst
index 705438d4a..fec7be3e5 100644
--- a/docs/handbook/image-file-formats.rst
+++ b/docs/handbook/image-file-formats.rst
@@ -535,8 +535,8 @@ The :py:meth:`~PIL.Image.Image.save` method supports the following options:
 PPM
 ^^^
 
-PIL reads and writes PBM, PGM and PPM files containing ``1``, ``L`` or ``RGB``
-data.
+PIL reads and writes PBM, PGM, PPM and PNM files containing ``1``, ``L`` or
+``RGB`` data.
 
 SGI
 ^^^