Merge multi images to a single image

main.py

def merge_and_save_image(bytes_list, save_path):
    img_list = []
    img_mode = 'RGB'
    img_width = 0
    img_height = [0]
    for i, bytes in enumerate(bytes_list):
        try:
            img = Image.open(io.BytesIO(bytes))
        except PIL.UnidentifiedImageError:
            continue
        img_list.append(img)
        img_mode = img.mode
        img_width = img_width if img_width > img.width else img.width
        img_height.append(img_height[-1] + img.height)

    long_img = Image.new(img_mode, (img_width, img_height[-1]))
    for i, img in enumerate(img_list):
        long_img.paste(img, (0, img_height[i]))

    long_img.save(save_path)