From 900b849aa8f915461630cf738a2927eca505beb2 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Thu, 22 Apr 2021 21:18:21 +1000
Subject: [PATCH] Use bpp from header

---
 Tests/images/black_and_white.ico | Bin 0 -> 198 bytes
 Tests/test_file_ico.py           |   6 ++++++
 src/PIL/IcoImagePlugin.py        |   8 +-------
 3 files changed, 7 insertions(+), 7 deletions(-)
 create mode 100644 Tests/images/black_and_white.ico

diff --git a/Tests/images/black_and_white.ico b/Tests/images/black_and_white.ico
new file mode 100644
index 0000000000000000000000000000000000000000..f98d7ac8e8d2234a25ac5b8c90c8c7914733878b
GIT binary patch
literal 198
xcmZQzU<5(|0VXiLfq{WR42U&=SOAC>fEXl?5B&fCA4OXJ2Ll5!7)29>8~~Bo4=Mlv

literal 0
HcmV?d00001

diff --git a/Tests/test_file_ico.py b/Tests/test_file_ico.py
index 5ace0c55e..edf3095f7 100644
--- a/Tests/test_file_ico.py
+++ b/Tests/test_file_ico.py
@@ -18,6 +18,12 @@ def test_sanity():
     assert im.get_format_mimetype() == "image/x-icon"
 
 
+def test_black_and_white():
+    with Image.open("Tests/images/black_and_white.ico") as im:
+        assert im.mode == "RGBA"
+        assert im.size == (16, 16)
+
+
 def test_invalid_file():
     with open("Tests/images/flower.jpg", "rb") as fp:
         with pytest.raises(SyntaxError):
diff --git a/src/PIL/IcoImagePlugin.py b/src/PIL/IcoImagePlugin.py
index 5634bf8e9..6e15a8bdb 100644
--- a/src/PIL/IcoImagePlugin.py
+++ b/src/PIL/IcoImagePlugin.py
@@ -190,13 +190,7 @@ class IcoFile:
             im.tile[0] = d, (0, 0) + im.size, o, a
 
             # figure out where AND mask image starts
-            mode = a[0]
-            bpp = 8
-            for k, v in BmpImagePlugin.BIT2MODE.items():
-                if mode == v[1]:
-                    bpp = k
-                    break
-
+            bpp = header["bpp"]
             if 32 == bpp:
                 # 32-bit color depth icon image allows semitransparent areas
                 # PIL's DIB format ignores transparency bits, recover them.