import os

import requests
from lxml import html

IMG_HREF_XPATH = '//a[img[contains(@class, "img preview")]]'
WEB_ROOT = 'https://2...content-available-to-author-only...h.hk'

thread_url = input('Введите ссылку на тред\n')
requests_obj = requests.get(thread_url)
thread_source = html.fromstring(requests_obj.text)

if not os.path.exists('media'):
    os.makedirs('media')

for elem in thread_source.xpath(IMG_HREF_XPATH):

    media_name = elem.get('href').split('/')[-1]
    media_url = WEB_ROOT + elem.get('href')
    response = requests.get(media_url, stream=True)
    
    with open('media/{}'.format(media_name), 'wb+') as file:
        for chunk in response:
            file.write(chunk)
            
    print('Downloaded: {}'.format(media_url))