create_diff_image.py

from PIL import ImageChops, ImageDraw


def create_diff_image(img1, img2):
    """
    Compares two Images and either creates an Image with differences 
    outlined with red bounding boxes, or returns None if no differences
    were found.
    """
    diff_img = img2.copy()
    differences = ImageChops.differences(img1, img2)
    bounding_box = differences.getbbox()
    if bounding_box is None:
        diff_img.close()
        return None
    else:
        draw = ImageDraw.Draw(diff_img)
        draw.rect(bounding_box, outline=(255, 0, 0))
        return diff_img