Problem with OpenCV 3 - Image output too large

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I try a very simple program which reads the image and outputs it. The problem I am having is that the resultant image outputted by the cv2.imshow() is very very large in size. I have tried ccv2.resizeWindow() with the parameters but it does not seem to work. I really hope you guys can help me! Thanks in advance! :)

import cv2
import numpy as np
img = cv2.imread('messi.jpg')
cv2.imshow('img',img)

cv2.waitKey(0)
cv2.destroyAllWindows()