From 922e239cca2a45d239dd02f0a4b85b72a7918917 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Wed, 24 May 2023 08:55:14 +1000
Subject: [PATCH] Fixed saving multiple 1 mode images to GIF

---
 Tests/test_file_gif.py    | 13 +++++++++++++
 src/PIL/GifImagePlugin.py |  2 +-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Tests/test_file_gif.py b/Tests/test_file_gif.py
index 8522f486a..0e50ee1ab 100644
--- a/Tests/test_file_gif.py
+++ b/Tests/test_file_gif.py
@@ -252,6 +252,19 @@ def test_roundtrip_save_all(tmp_path):
         assert reread.n_frames == 5
 
 
+def test_roundtrip_save_all_1(tmp_path):
+    out = str(tmp_path / "temp.gif")
+    im = Image.new("1", (1, 1))
+    im2 = Image.new("1", (1, 1), 1)
+    im.save(out, save_all=True, append_images=[im2])
+
+    with Image.open(out) as reloaded:
+        assert reloaded.getpixel((0, 0)) == 0
+
+        reloaded.seek(1)
+        assert reloaded.getpixel((0, 0)) == 255
+
+
 @pytest.mark.parametrize(
     "path, mode",
     (
diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index eadee1560..2f92e9467 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -879,7 +879,7 @@ def _get_palette_bytes(im):
     :param im: Image object
     :returns: Bytes, len<=768 suitable for inclusion in gif header
     """
-    return im.palette.palette
+    return im.palette.palette if im.palette else b""
 
 
 def _get_background(im, info_background):