img.shape img.size

import cv2
import numpy as np
img=cv2.imread('messi5.jpg')
print img.shape
px=img[100,100]
print px
blue=img[100,100,0]
print blue
## [57 63 68]
## 57
print img[100,100]
img[100,100]=[255,255,255]
print img[100,100]
## [255 255 255]
print img.shape
print img.size