From 804183c2489242251fdd9858b6e781ceefb08c8b Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sun, 27 Jun 2021 18:29:02 +1000
Subject: [PATCH] Only use an RGBA palette for images with an alpha channel

---
 Tests/test_file_apng.py     | 4 ++--
 Tests/test_image_convert.py | 2 +-
 src/PIL/Image.py            | 2 +-
 src/PIL/WebPImagePlugin.py  | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/Tests/test_file_apng.py b/Tests/test_file_apng.py
index 8348da4eb..7fb6f59d4 100644
--- a/Tests/test_file_apng.py
+++ b/Tests/test_file_apng.py
@@ -249,8 +249,8 @@ def test_apng_mode():
         assert im.mode == "P"
         im.seek(im.n_frames - 1)
         im = im.convert("RGBA")
-        assert im.getpixel((0, 0)) == (0, 255, 0, 255)
-        assert im.getpixel((64, 32)) == (0, 255, 0, 255)
+        assert im.getpixel((0, 0)) == (255, 0, 0, 0)
+        assert im.getpixel((64, 32)) == (255, 0, 0, 0)
 
     with Image.open("Tests/images/apng/mode_palette_1bit_alpha.png") as im:
         assert im.mode == "P"
diff --git a/Tests/test_image_convert.py b/Tests/test_image_convert.py
index 01bcbb95f..20ef3a57f 100644
--- a/Tests/test_image_convert.py
+++ b/Tests/test_image_convert.py
@@ -167,7 +167,7 @@ def test_gif_with_rgba_palette_to_p():
     with Image.open("Tests/images/hopper.gif") as im:
         im.info["transparency"] = 255
         im.load()
-        assert im.palette.mode == "RGBA"
+        assert im.palette.mode == "RGB"
         im_p = im.convert("P")
 
     # Should not raise ValueError: unrecognized raw mode
diff --git a/src/PIL/Image.py b/src/PIL/Image.py
index 5c63c91b5..76814a8cc 100644
--- a/src/PIL/Image.py
+++ b/src/PIL/Image.py
@@ -833,7 +833,7 @@ class Image:
             palette_length = self.im.putpalette(mode, arr)
             self.palette.dirty = 0
             self.palette.rawmode = None
-            if "transparency" in self.info:
+            if "transparency" in self.info and mode in ("RGBA", "LA", "PA"):
                 if isinstance(self.info["transparency"], int):
                     self.im.putpalettealpha(self.info["transparency"], 0)
                 else:
diff --git a/src/PIL/WebPImagePlugin.py b/src/PIL/WebPImagePlugin.py
index 50b82feb0..b63a07ca8 100644
--- a/src/PIL/WebPImagePlugin.py
+++ b/src/PIL/WebPImagePlugin.py
@@ -320,7 +320,7 @@ def _save(im, fp, filename):
         alpha = (
             "A" in im.mode
             or "a" in im.mode
-            or (im.mode == "P" and "A" in im.im.getpalettemode())
+            or (im.mode == "P" and "transparency" in im.info)
         )
         im = im.convert("RGBA" if alpha else "RGB")