Python - Como puedo usar Threading y Queue para realizar descargas simultaneas por hilos

import threading

import urllib.request

def worker(cont):

    print("La funcion esta ON")

    imagen_download = "https://unab-dw2018.s3.amazonaws.com/ldp2019/"+str(cont)+".jpeg"

    download = urllib.request.urlopen(imagen_download)

    file_save = open("Imagen "+str(cont)+".jpeg","wb")

    file_save.write(download.read())

    file_save.close()

    return cont+1

hilos = []

cant_hilos = int(input("Ingrese la cantidad de hilos a utilizar, entre 4 y 6"))

for i in range (0,cant_hilos):

    h = threading.Thread(target=worker, args= (i+1,))

    hilos.append(h)

for i in range(0,cant_hilos):

    hilos[i].start()

import threading

import queue

if __name__ == "__main__":

    picture_queue = queue.Queue(maxsize=0)

    picture_threads = []

    picture_urls = ["https://unab-dw2018.s3.amazonaws.com/ldp2019/1.jpeg",

                    "https://unab-dw2018.s3.amazonaws.com/ldp2019/2.jpeg"]

    # create and start the threads

    for url in picture_urls:

        picture_threads.append(picture_getter(url, picture_queue))

        picture_threads[i].start()

    # wait for threads to finish

    for picture_thread in picture_threads:

        picture_thread.join()

    # get the results

    picture_list = []

    while not picture_queue.empty():

        picture_list.append(picture_queue.get())

class picture_getter(threading.Thread):

    def __init__(self, url, picture_queue):

        self.url = url

        self.picture_queue = picture_queue

        super(picture_getter, self).__init__()

    def run(self):

        print("Starting download on " + str(self.url))

        self._get_picture()

    def _get_picture(self):

        # --- get your picture --- #

        self.picture_queue.put(picture)