How to insert an image (a picture or a photo) in a matplotlib figure

To insert an image in matplotlib figure, there is the annotation function. Example, using Lena picture:

from matplotlib.offsetbox import TextArea, DrawingArea, OffsetImage, AnnotationBbox

import matplotlib.pyplot as plt
import matplotlib.image as mpimg

fig, ax = plt.subplots()

ax.set_xlim(0, 1)
ax.set_ylim(0, 1)

arr_lena = mpimg.imread('Lenna.png')

imagebox = OffsetImage(arr_lena, zoom=0.2)

ab = AnnotationBbox(imagebox, (0.4, 0.6))

ax.add_artist(ab)

plt.grid()

plt.draw()
plt.savefig('add_picture_matplotlib_figure.png',bbox_inches='tight')
plt.show()

References