Вот пример сценария, который можно использовать для сохранения файла captcha.jpg.
import requests
import shutil
url = "https://servicesenligne2.ville.montreal.qc.ca/sel/evalweb/createimage.png?timestamp=1583203496087"
# we are able to use the same cookie even after refreshing (so you should be good to use the same cookie)
headers = {
'Cookie': 'JSESSIONID=YB-eSDCWKU-SG_bKEtluH8kzvWMop4B0plLN4NOLXtO09plZSEuS!-209918963'
}
response = requests.get(url,headers=headers, stream=True)
with open("captcha.jpg", 'wb') as f:
response.raw.decode_content = True
shutil.copyfileobj(response.raw, f)

Ниже приведен полный код.
from selenium import webdriver
import requests
import shutil
driver = webdriver.Chrome()
driver.get('https://servicesenligne2.ville.montreal.qc.ca/sel/evalweb/index')
img = driver.find_element_by_xpath('//*[@id="type_recherche"]/div[5]/div/img')
src = img.get_attribute('src')
jsession = driver.get_cookie('JSESSIONID')['value']
headers = {
'Cookie': 'JSESSIONID='+jsession
}
response = requests.get(src,headers=headers, stream=True)
with open("captcha.jpg", 'wb') as f:
response.raw.decode_content = True
shutil.copyfileobj(response.raw, f)