5. ImageChops composite

See: https://pillow.readthedocs.io/en/stable/reference/ImageChops.html#PIL.ImageChops.composite
See: Image.composite()

5.1. Composite

Alias for Image.composite().
Use the ImageChops.composite(image1, image2, mask) method to create a composite image by blending images using a transparency mask. Here, mask is another image which remains transparent.
The second image, must have the same mode and size as the first image.
The mask image can have mode “1”, “L”, or “RGBA”, and must have the same size as the other two images.
In the example below the mask goes from black, 0 (fully transparent) to white, 255 (fully opaque) from left to right.
image1 follows the mask transparency.
image2 follows the mask transparency in reverse.
from PIL import Image, ImageChops

with Image.open("test_images/crosses.png") as im1:
    with Image.open("test_images/circles.png") as im2:
        with Image.open("test_images/greyscale_vert_gradient_32.png") as mask:
            im_out = ImageChops.composite(im1, im2, mask)
            im_out.save("chops/composite.png")
../_images/compare_composite.png