From dd00829f1eb8a17007bd19da3e9a02b0b99f6e99 Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Sat, 19 Dec 2020 19:42:07 +0100
Subject: [PATCH] Ignore PhotoPathSize thumbnail sizes

Closes #1655.
---
 telethon/client/downloads.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/telethon/client/downloads.py b/telethon/client/downloads.py
index d0fe2bac..6c61258a 100644
--- a/telethon/client/downloads.py
+++ b/telethon/client/downloads.py
@@ -733,6 +733,13 @@ class DownloadMethods:
 
         thumbs = list(sorted(thumbs, key=sort_thumbs))
 
+        for i in reversed(range(len(thumbs))):
+            # :tl:`PhotoPathSize` is used for animated stickers preview, and the thumb is actually
+            # a SVG path of the outline. Users expect thumbnails to be JPEG files, so pretend this
+            # thumb size doesn't actually exist (#1655).
+            if isinstance(thumbs[i], types.PhotoPathSize):
+                thumbs.pop(i)
+
         if thumb is None:
             return thumbs[-1]
         elif isinstance(thumb, int):