diff --git a/src/pptx/parts/image.py b/src/pptx/parts/image.py
index 9be5d02d..99146b7b 100644
--- a/src/pptx/parts/image.py
+++ b/src/pptx/parts/image.py
@@ -230,6 +230,7 @@ def ext(self) -> str:
             "PNG": "png",
             "TIFF": "tiff",
             "WMF": "wmf",
+            "MPO": "jpg",
         }
         format = self._format
         if format not in ext_map: