Renamed the method setStickerSetThumb to setStickerSetThumbnail and its parameter thumb to thumbnail.

telebot/__init__.py

@@ -4537,7 +4537,7 @@ class TeleBot:
         """
         return apihelper.answer_callback_query(self.token, callback_query_id, text, show_alert, url, cache_time)
 
-    def set_sticker_set_thumb(
+    def set_sticker_set_thumbnail(
             self, name: str, user_id: int, thumb: Union[Any, str]=None):
         """
         Use this method to set the thumbnail of a sticker set. 
@@ -4558,6 +4558,8 @@ class TeleBot:
         :rtype: :obj:`bool`
         """
         return apihelper.set_sticker_set_thumb(self.token, name, user_id, thumb)
+    
+    set_sticker_set_thumb = set_sticker_set_thumbnail
 
     def get_sticker_set(self, name: str) -> types.StickerSet:
         """

telebot/apihelper.py

@@ -356,7 +356,7 @@ def get_chat_member_count(token, chat_id):
 
 
 def set_sticker_set_thumb(token, name, user_id, thumb):
-    method_url = r'setStickerSetThumb'
+    method_url = r'setStickerSetThumbnail'
     payload = {'name': name, 'user_id': user_id}
     files = {}
     if thumb:

telebot/async_telebot.py

@@ -5401,7 +5401,7 @@ class AsyncTeleBot:
         """
         return await asyncio_helper.answer_callback_query(self.token, callback_query_id, text, show_alert, url, cache_time)
 
-    async def set_sticker_set_thumb(
+    async def set_sticker_set_thumbnail(
             self, name: str, user_id: int, thumb: Union[Any, str]=None):
         """
         Use this method to set the thumbnail of a sticker set. 
@@ -5422,6 +5422,8 @@ class AsyncTeleBot:
         :rtype: :obj:`bool`
         """
         return await asyncio_helper.set_sticker_set_thumb(self.token, name, user_id, thumb)
+    
+    set_sticker_set_thumb = set_sticker_set_thumbnail
 
     async def get_sticker_set(self, name: str) -> types.StickerSet:
         """

telebot/asyncio_helper.py

@@ -342,7 +342,7 @@ async def get_chat_member_count(token, chat_id):
 
 
 async def set_sticker_set_thumb(token, name, user_id, thumb):
-    method_url = r'setStickerSetThumb'
+    method_url = r'setStickerSetThumbnail'
     payload = {'name': name, 'user_id': user_id}
     files = {}
     if thumb: