import cv2
import numpy as np
img = cv2.imread("lena.jpg", cv2.IMREAD_COLOR) # rgb
alpha_img = cv2.imread("lena.jpg", cv2.IMREAD_UNCHANGED) # rgba
gray_img = cv2.imread("lena.jpg", cv2.IMREAD_GRAYSCALE) # grayscale
print type(img)
print 'RGB shape: ', img.shape # Rows, cols, channels
print 'ARGB shape:', alpha_img.shape
print 'Gray shape:', gray_img.shape
print 'img.dtype: ', img.dtype
print 'img.size: ', img.size