From b33ebc8c71b7132b7e19271720c0073f0e7e5dd5 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 25 Feb 2022 16:26:02 +1100
Subject: [PATCH] Fixed reading uncompressed BLP2 with alpha

---
 Tests/test_file_blp.py    | 16 ++++++++++++++--
 src/PIL/BlpImagePlugin.py |  5 ++++-
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/Tests/test_file_blp.py b/Tests/test_file_blp.py
index 22ddcb69152..c07232dd6bd 100644
--- a/Tests/test_file_blp.py
+++ b/Tests/test_file_blp.py
@@ -2,7 +2,12 @@
 
 from PIL import BlpImagePlugin, Image
 
-from .helper import assert_image_equal, assert_image_equal_tofile, hopper
+from .helper import (
+    assert_image_equal,
+    assert_image_similar,
+    assert_image_equal_tofile,
+    hopper,
+)
 
 
 def test_load_blp1():
@@ -31,7 +36,14 @@ def test_save(tmp_path):
     im.save(f)
 
     with Image.open(f) as reloaded:
-        assert_image_equal(im, reloaded.convert("RGB"))
+        assert_image_equal(im.convert("RGB"), reloaded)
+
+    with Image.open("Tests/images/transparent.png") as im:
+        f = str(tmp_path / "temp.blp")
+        im.convert("P").save(f)
+
+        with Image.open(f) as reloaded:
+            assert_image_similar(im, reloaded, 8)
 
 
 @pytest.mark.parametrize(
diff --git a/src/PIL/BlpImagePlugin.py b/src/PIL/BlpImagePlugin.py
index dfd6518671f..f83f1979e9b 100644
--- a/src/PIL/BlpImagePlugin.py
+++ b/src/PIL/BlpImagePlugin.py
@@ -406,7 +406,10 @@ def _load(self):
                     except struct.error:
                         break
                     b, g, r, a = palette[offset]
-                    data.extend((r, g, b))
+                    d = (r, g, b)
+                    if self._blp_alpha_depth:
+                        d += (a,)
+                    data.extend(d)
 
             elif self._blp_encoding == Encoding.DXT:
                 if self._blp_alpha_encoding == AlphaEncoding.DXT1: