plt.imshow : a key function provided by Matplotlib

One of key functions provided by Matplotlib include imshow() which a function for displaying 2D arrays as images.

Matplotlib is a plotting library for Python that provides a variety of functions and tools for creating static, animated, and interactive visualizations.

plt.imshow can be used to display JPEG images in addition to other image formats such as PNG, BMP, and GIF.

To display a JPEG image using plt.imshow, you can use the matplotlib.image.imread() function to read the JPEG file and convert it to a numpy array of pixel values, and then pass this array to plt.imshow() as follows:

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

# Load a JPEG image using matplotlib.image.imread
img = mpimg.imread('example.jpg')

# Display the image using plt.imshow
plt.imshow(img)
plt.show()

In this example, we first load a JPEG image called example.jpg using the mpimg.imread() function, which returns a numpy array representing the image pixels. We then pass this array to plt.imshow() to display the image in a plot. Finally, we call plt.show() to show the plot.

Note that mpimg.imread() assumes that the pixel values in the JPEG file represent color intensities in the range [0, 255], and maps them to colors using a default colormap. However, you can customize the colormap and other display options using additional arguments to plt.imshow().

To use plt.imshow() to display a JPEG image that has pixel normalized values in the range -1 to 1, you need to convert normalized values from the range [-1, 1] to the range [1, 0], and you can use the following formula:
new_value = (old_value + 1) / 2