From 07b24c6e6e266999dbaaa12ffb201f402190cad1 Mon Sep 17 00:00:00 2001
From: ziplantil <magnoboost@gmail.com>
Date: Sun, 19 Apr 2020 16:29:36 +0300
Subject: [PATCH] add append_images support for ico, much like icns

---
 src/PIL/IcoImagePlugin.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/PIL/IcoImagePlugin.py b/src/PIL/IcoImagePlugin.py
index e4a74321b..0186751be 100644
--- a/src/PIL/IcoImagePlugin.py
+++ b/src/PIL/IcoImagePlugin.py
@@ -52,6 +52,9 @@ def _save(im, fp, filename):
     sizes = list(sizes)
     fp.write(struct.pack("<H", len(sizes)))  # idCount(2)
     offset = fp.tell() + len(sizes) * 16
+    alt_images = {
+        im.size: im for im in im.encoderinfo.get("append_images", [])
+    }
     for size in sizes:
         width, height = size
         # 0 means 256
@@ -63,9 +66,12 @@ def _save(im, fp, filename):
         fp.write(struct.pack("<H", 32))  # wBitCount(2)
 
         image_io = BytesIO()
-        # TODO: invent a more convenient method for proportional scalings
-        tmp = im.copy()
-        tmp.thumbnail(size, Image.LANCZOS, reducing_gap=None)
+        if size in alt_images:
+            tmp = alt_images[size]
+        else:
+            # TODO: invent a more convenient method for proportional scalings
+            tmp = im.copy()
+            tmp.thumbnail(size, Image.LANCZOS, reducing_gap=None)
         tmp.save(image_io, "png")
         image_io.seek(0)
         image_bytes = image_io.read()