from selenium import webdriver
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary
import random

profile = webdriver.FirefoxProfile()
capabilities = webdriver.DesiredCapabilities().FIREFOX
capabilities["marionette"] = False

driver = webdriver.Firefox(profile, capabilities=capabilities)

# Random window size
screen_sizes = [[1280, 720], [1920, 1080], [640, 480], [800, 600], [960, 720], [1024, 768], [1280, 960]]
random_screen_size = random.randint(0, 6)
driver.set_window_size(screen_sizes[random_screen_size][0], screen_sizes[random_screen_size][1])

drivet.get('http://www.google.com')