"Wrong persistent file_id specified: wrong string length" when send PhotoSize to user

[vartagg]

Steps to reproduce

1. Handle Photo sending by user to your bot and save all of PhotoSize data anywhere

2. Then send any of these photo-sizes by its file_id like update.effective_message.reply_photo(update.effective_user.id, saved_photo_size_file_id) from your bot to user

Expected behaviour

Photo should be sent from bot to user

Actual behaviour

Error from Telegram API: "Wrong persistent file_id specified: wrong string length"

Configuration

Operating System:
macOS Sierra

Version of Python, python-telegram-bot & dependencies:

python-telegram-bot 8.0
certifi 2017.07.27.1
future 0.16.0
Python 3.6.0 (v3.6.0:41df79263a11, Dec 22 2016, 17:23:13)  [GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]

I found that Telegram bot API don't allow to resend thumbnails (PhotoSize): https://core.telegram.org/bots/api#sending-files

Sending by file_id

It is not possible to change the file type when resending by file_id. I.e. a video can't be sent as a photo, a photo can't be sent as a document, etc.
It is not possible to resend thumbnails
Resending a photo by file_id will send all of its sizes.
file_id is unique for each individual bot and can't be transferred from one bot to another.

But effective_attachment of message sending by user has only list of PhotoSize and don't storing file_id of original Photo.

So how to extract file_id of original Photo for resend this in future?

[jh0ker]

@vartagg I think you are using the reply_photo method wrong, because why are you passing the user ID in there?

[Eldinnie]

It's like @jh0ker said. you're passing the users id as a file_id to the bot. telegram rejects it for obvious reasons

[vartagg]

@jh0ker @Eldinnie That's it, thank you! Sending image to user by PhotoSize's file_id is working, probably telegram developers meant something else when say "It is not possible to resend thumbnails"