subplot-mosaic-2.py

import matplotlib.pyplot as plt

image = plt.imread("gardens.jpg")

# Create a figure with two subplots using 'subplot_mosaic'
# Argument needs to be a 2D array, which is why
# there are two sets of square brackets
fig, ax = plt.subplot_mosaic(
    [["Left", "Right"]]
)

# You can now use a "dictionary-style" indexing
# to refer to each subplot
ax["Left"].imshow(image)
ax["Left"].axis("off")

# Extract the red channel from the image
image_red = image.copy()
image_red[:, :, 1:] = 0

ax["Right"].imshow(image_red)
ax["Right"].axis("off")

plt.show()