I am scraping image and trying to convert them into grayscale. But if i view the image. It is plain black. Can someone tell me what is wrong with this? Thanks

Here is my snippet

```
import cv2
from skimage import io
from skimage import data
from skimage.color import rgb2gray

#...some codes

for i in elements:
    try:
        i.click()
    except ElementClickInterceptedException:
        driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
        i.click()
    url = driver.find_element_by_xpath('//*[@class="slider-list"]/div/img').get_attribute('src').replace('height=600','height=1200').replace('quality=70','quality=100')
    print (url)
    name = driver.find_element_by_xpath('//*[@class="slider-list"]/div/img').get_attribute('alt') + '.jpg'

    print (name)
    img = io.imread(url)
    new = rgb2gray(img)
    cv2.imwrite(os.path.join(fldrnm, name), new)

```