# your imports
...
from selenium import webdriver
site = 'http://heroimages.com/portfolio'
directory = "pixabay/" #Relative to script location
driver = webdriver.Chrome('/usr/local/bin/chromedriver')
driver.get(site)
soup = BeautifulSoup(driver.page_source, 'html.parser')
img_tags = soup.find_all('img')
urls = [img['src'] for img in img_tags]
for url in urls:
print(url)
# your code
...