We can retrieve and use many image properties with OpenCV functions. Take a look at the following code:

import cv2
img = cv2.imread('lena_color_512.tif',1)
print img.shape
print img.size
print img.dtype

The img.shape operation returns the shape of the image, that is, its dimensions and the number of color channels. The output of the previously listed code will be as follows:

(512, 512, 3)
786432
uint8

If the image is colored, then img.shape returns a triplet containing the number of rows, the number of columns, and the number of channels in the image. Usually, the number of channels is three, representing the red, green, and blue channels. If the image is grayscale, then img.shape only returns the number of rows and the number of columns. Try to modify the preceding code to read the image in the grayscale mode and observe the output of img.shape.

The img.size operation returns the total number of pixels, and img.dtype returns the image datatype.