PIL库与OpenCV库读取图片的区别
用PIL库（Pillow：【pip install pillow】）读取图片：
from PIL import Image
img = Image.open(img_path)
size = img.size
w = img.size[0]
h = img.size[1]用OpenCV库读取图片：
import cv2
img = cv2.imread(img_path)
size = img.size
w = img.size[1]
h = img.size[0]区别在于：两者的w和h的位置是不同的！！