You can open an image using the Image class from the package PIL and display it with plt.imshow directly.
# First import libraries.
from PIL import Image
import matplotlib.pyplot as plt
# The folliwing line is useful in Jupyter notebook
%matplotlib inline
# Open your file image using the path
img = Image.open(<path_to_image>)
# Since plt knows how to handle instance of the Image class, just input your loaded image to imshow method
plt.imshow(img)