diff --git a/src/PIL/Image.py b/src/PIL/Image.py
index 7d2bb1e7e..8b92aae45 100644
--- a/src/PIL/Image.py
+++ b/src/PIL/Image.py
@@ -2110,7 +2110,7 @@ class Image(object):
         debugging purposes.
 
         On Unix platforms, this method saves the image to a temporary
-        PPM file, and calls the **display**, **eog** or **xv**
+        PNG file, and calls the **display**, **eog** or **xv**
         utility, depending on which one can be found.
 
         On macOS, this method saves the image to a temporary PNG file, and