how to save the captcha image with selenium webdriver. python

I have faced with some problem. I have captcha image, and it`s 'src', but how to get this 'src' and save whole image?

My code:

import os, urllib.request, requests, datetime, time, random, ssl, json, codecs, csv, urllib
from urllib.request import Request, urlopen
from urllib.request import urlretrieve
from datetime import datetime
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait 
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import NoAlertPresentException
from selenium.webdriver.chrome.options import Options
from PIL import Image

chromedriver = "chromedriver"
os.environ["webdriver.chrome.driver"] = chromedriver
options = webdriver.ChromeOptions() 
options.add_argument("start-maximized")
options.add_argument('disable-infobars')
chromedriver = "chromedriver"
os.environ["webdriver.chrome.driver"] = chromedriver
chrome_options = webdriver.ChromeOptions()
driver = webdriver.Chrome(executable_path=chromedriver, chrome_options=chrome_options)
driver.get("https://www.inipec.gov.it/cerca-pec/-/pecs/companies")
WebDriverWait(driver, 10).until(EC.frame_to_be_available_and_switch_to_it((By.CSS_SELECTOR,"iframe[name^='a-'][src^='https://www.google.com/recaptcha/api2/anchor?']")))
WebDriverWait(driver, 10).until(EC.element_to_be_clickable((By.XPATH, "//span[@class='recaptcha-checkbox goog-inline-block recaptcha-checkbox-unchecked rc-anchor-checkbox']/div[@class='recaptcha-checkbox-checkmark']"))).click()
time.sleep(5)
img = driver.find_element_by_xpath('//*[@id="rc-imageselect-target"]/table/tbody/tr[1]/td[2]/div/div[1]/img')
src = img.get_attribute('src')
urllib.request.urlretrieve(src, "captcha.png")