From dfda61a1b50d846e19593263e5b363d4cfbfe00f Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Sat, 7 Jul 2018 12:01:42 +0200
Subject: [PATCH] Correct thumb parameter documentation

---
 telethon/client/uploads.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/telethon/client/uploads.py b/telethon/client/uploads.py
index 17b361ef..52cc8203 100644
--- a/telethon/client/uploads.py
+++ b/telethon/client/uploads.py
@@ -72,7 +72,8 @@ class UploadMethods(MessageParseMethods, UserMethods):
                 :tl:`DocumentAttributeFilename` and so on.
 
             thumb (`str` | `bytes` | `file`, optional):
-                Optional thumbnail (for videos).
+                Optional JPEG thumbnail (for documents). **Telegram will
+                ignore this parameter** unless you pass a ``.jpg`` file!
 
             allow_cache (`bool`, optional):
                 Whether to allow using the cached version stored in the