Don't ignore thumb in send_file(input file)

Fixes #1404

telethon/client/uploads.py

@@ -637,6 +637,14 @@ class UploadMethods:
         if as_image is None:
             as_image = utils.is_image(file) and not force_document
 
+        if as_image or not thumb:
+            # Images don't have thumb so don't bother uploading it
+            thumb = None
+        else:
+            if isinstance(thumb, pathlib.Path):
+                thumb = str(thumb.absolute())
+            thumb = await self.upload_file(thumb)
+
         # `aiofiles` do not base `io.IOBase` but do have `read`, so we
         # just check for the read attribute to see if it's file-like.
         if not isinstance(file, (str, bytes)) and not hasattr(file, 'read'):
@@ -654,7 +662,8 @@ class UploadMethods:
                     force_document=force_document,
                     voice_note=voice_note,
                     video_note=video_note,
-                    supports_streaming=supports_streaming
+                    supports_streaming=supports_streaming,
+                    thumb=thumb,
                 ), as_image)
             except TypeError:
                 # Can't turn whatever was given into media
@@ -699,17 +708,11 @@ class UploadMethods:
                 supports_streaming=supports_streaming
             )
 
-            input_kw = {}
-            if thumb:
-                if isinstance(thumb, pathlib.Path):
-                    thumb = str(thumb.absolute())
-                input_kw['thumb'] = await self.upload_file(thumb)
-
             media = types.InputMediaUploadedDocument(
                 file=file_handle,
                 mime_type=mime_type,
                 attributes=attributes,
-                **input_kw
+                thumb=thumb
             )
         return file_handle, media, as_image
 

telethon/utils.py

@@ -427,7 +427,8 @@ def get_input_geo(geo):
 def get_input_media(
         media, *,
         is_photo=False, attributes=None, force_document=False,
-        voice_note=False, video_note=False, supports_streaming=False
+        voice_note=False, video_note=False, supports_streaming=False,
+        thumb=None,
 ):
     """
     Similar to :meth:`get_input_peer`, but for media.
@@ -481,7 +482,7 @@ def get_input_media(
                 supports_streaming=supports_streaming
             )
             return types.InputMediaUploadedDocument(
-                file=media, mime_type=mime, attributes=attrs)
+                file=media, mime_type=mime, attributes=attrs, thumb=thumb)
 
     if isinstance(media, types.MessageMediaGame):
         return types.InputMediaGame(id=types.InputGameID(