import requests
import telegram

bot = telegram.Bot("<TOKEN>")
update = telegram.Update.de_json(request.get_json(force=True), bot)
chat_id = update.message.chat.id
response = requests.get('https://source.unsplash.com/random')

bot.send_photo(chat_id, response.content)

$ python -m telegram
python-telegram-bot 13.1
certifi 2020.11.08
Python 3.6.12 (default, Aug 18 2020, 11:10:29) [GCC 7.5.0] 

Traceback (most recent call last):
  File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/app/.heroku/python/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/app/app.py", line 9, in mybot_respond
    return mybot.respond()
  File "/app/bots/mybot.py", line 30, in respond
    bot.send_photo(chat_id, response.content) 
  File "<decorator-gen-5>", line 2, in send_photo
  File "/app/.heroku/python/lib/python3.6/site-packages/telegram/bot.py", line 135, in decorator
    result = func(*args, **kwargs)
  File "/app/.heroku/python/lib/python3.6/site-packages/telegram/bot.py", line 639, in send_photo
    api_kwargs=api_kwargs,
  File "/app/.heroku/python/lib/python3.6/site-packages/telegram/bot.py", line 281, in _message
    result = self._post(endpoint, data, timeout=timeout, api_kwargs=api_kwargs)
  File "/app/.heroku/python/lib/python3.6/site-packages/telegram/bot.py", line 245, in _post
    return self.request.post(f'{self.base_url}/{endpoint}', data=data, timeout=timeout)
  File "/app/.heroku/python/lib/python3.6/site-packages/telegram/utils/request.py", line 352, in post
    body=json.dumps(data).encode('utf-8'),
  File "/app/.heroku/python/lib/python3.6/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/app/.heroku/python/lib/python3.6/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/app/.heroku/python/lib/python3.6/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/app/.heroku/python/lib/python3.6/json/encoder.py", line 180, in default
    o.__class__.__name__)
TypeError: Object of type 'bytes' is not JSON serializable