From bcc6e42bf82dfc962d49ed1876a946bd7be16b4f Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Tue, 27 May 2025 21:08:58 +1000
Subject: [PATCH 1/3] Fixed saving MPO with more than one appended image

---
 Tests/test_file_mpo.py    | 18 ++++++++++--------
 src/PIL/MpoImagePlugin.py | 13 ++++++++++---
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/Tests/test_file_mpo.py b/Tests/test_file_mpo.py
index 73838ef44..adfa61962 100644
--- a/Tests/test_file_mpo.py
+++ b/Tests/test_file_mpo.py
@@ -293,16 +293,18 @@ def test_save_all() -> None:
             assert_image_similar(im, im_reloaded, 30)
 
     im = Image.new("RGB", (1, 1))
-    im2 = Image.new("RGB", (1, 1), "#f00")
-    im_reloaded = roundtrip(im, save_all=True, append_images=[im2])
+    for colors in (("#f00",), ("#f00", "#0f0")):
+        append_images = (Image.new("RGB", (1, 1), color) for color in colors)
+        im_reloaded = roundtrip(im, save_all=True, append_images=append_images)
 
-    assert_image_equal(im, im_reloaded)
-    assert isinstance(im_reloaded, MpoImagePlugin.MpoImageFile)
-    assert im_reloaded.mpinfo is not None
-    assert im_reloaded.mpinfo[45056] == b"0100"
+        assert_image_equal(im, im_reloaded)
+        assert isinstance(im_reloaded, MpoImagePlugin.MpoImageFile)
+        assert im_reloaded.mpinfo is not None
+        assert im_reloaded.mpinfo[45056] == b"0100"
 
-    im_reloaded.seek(1)
-    assert_image_similar(im2, im_reloaded, 1)
+        for im_expected in append_images:
+            im_reloaded.seek(im_reloaded.tell() + 1)
+            assert_image_similar(im_reloaded, im_expected, 1)
 
     # Test that a single frame image will not be saved as an MPO
     jpg = roundtrip(im, save_all=True)
diff --git a/src/PIL/MpoImagePlugin.py b/src/PIL/MpoImagePlugin.py
index f7393eac0..f96f658fc 100644
--- a/src/PIL/MpoImagePlugin.py
+++ b/src/PIL/MpoImagePlugin.py
@@ -19,7 +19,6 @@
 #
 from __future__ import annotations
 
-import itertools
 import os
 import struct
 from typing import IO, Any, cast
@@ -47,12 +46,20 @@ def _save_all(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
 
     mpf_offset = 28
     offsets: list[int] = []
-    for imSequence in itertools.chain([im], append_images):
+    total = 0
+    imSequences = [im] + list(append_images)
+    for imSequence in imSequences:
+        total += getattr(imSequence, "n_frames", 1)
+    for imSequence in imSequences:
         for im_frame in ImageSequence.Iterator(imSequence):
             if not offsets:
                 # APP2 marker
+                ifd_length = 66 + 16 * total
                 im_frame.encoderinfo["extra"] = (
-                    b"\xff\xe2" + struct.pack(">H", 6 + 82) + b"MPF\0" + b" " * 82
+                    b"\xff\xe2"
+                    + struct.pack(">H", 6 + ifd_length)
+                    + b"MPF\0"
+                    + b" " * ifd_length
                 )
                 exif = im_frame.encoderinfo.get("exif")
                 if isinstance(exif, Image.Exif):

From 41129ce1cb88ae6f7733b40f3f6a9f1a5662d2af Mon Sep 17 00:00:00 2001
From: Andrew Murray <3112309+radarhere@users.noreply.github.com>
Date: Sat, 28 Jun 2025 01:20:02 +1000
Subject: [PATCH 2/3] Use list

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
---
 Tests/test_file_mpo.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tests/test_file_mpo.py b/Tests/test_file_mpo.py
index adfa61962..840202214 100644
--- a/Tests/test_file_mpo.py
+++ b/Tests/test_file_mpo.py
@@ -294,7 +294,7 @@ def test_save_all() -> None:
 
     im = Image.new("RGB", (1, 1))
     for colors in (("#f00",), ("#f00", "#0f0")):
-        append_images = (Image.new("RGB", (1, 1), color) for color in colors)
+        append_images = [Image.new("RGB", (1, 1), color) for color in colors]
         im_reloaded = roundtrip(im, save_all=True, append_images=append_images)
 
         assert_image_equal(im, im_reloaded)

From 5732a86cc6f8aad4a28a92b7c7c78748000c8d1d Mon Sep 17 00:00:00 2001
From: Andrew Murray <3112309+radarhere@users.noreply.github.com>
Date: Sat, 28 Jun 2025 10:52:25 +1000
Subject: [PATCH 3/3] Use snake case

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
---
 src/PIL/MpoImagePlugin.py | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/PIL/MpoImagePlugin.py b/src/PIL/MpoImagePlugin.py
index f96f658fc..784b6f208 100644
--- a/src/PIL/MpoImagePlugin.py
+++ b/src/PIL/MpoImagePlugin.py
@@ -46,12 +46,10 @@ def _save_all(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
 
     mpf_offset = 28
     offsets: list[int] = []
-    total = 0
-    imSequences = [im] + list(append_images)
-    for imSequence in imSequences:
-        total += getattr(imSequence, "n_frames", 1)
-    for imSequence in imSequences:
-        for im_frame in ImageSequence.Iterator(imSequence):
+    im_sequences = [im, *append_images]
+    total = sum(getattr(seq, "n_frames", 1) for seq in im_sequences)
+    for im_sequence in im_sequences:
+        for im_frame in ImageSequence.Iterator(im_sequence):
             if not offsets:
                 # APP2 marker
                 ifd_length = 66 + 16 * total