Turn a Long Image into a GIF with Python’s PIL: Step‑by‑Step Guide

In anticipation of the “network Valentine’s Day” (520), the author shares a light‑hearted view before diving into a practical Python tutorial.

Splitting a Long Image

The long picture consists of 16 dialogue frames. By cropping the image into equal‑height slices using Image.crop(), each slice can be saved as a separate PNG. The cropping box is defined as (left, upper, right, lower) coordinates.

import os
from PIL import Image

def split_image(file, split_times):
    path, filename = os.path.split(file)
    os.chdir(path)
    try:
        os.mkdir('pictures')
    except FileExistsError:
        pass
    img = Image.open(filename)
    width, height = img.size
    per_height = height / split_times
    for pictureNumber in range(split_times):
        _cropBox = (0, per_height * pictureNumber, width * 0.8, per_height * (pictureNumber + 1))
        picture = img.crop(_cropBox)
        picture_name = os.path.join(path, 'pictures', "%d.png" % pictureNumber)
        picture.save(picture_name)

split_image("C:\\Users\\Administrator\\Downloads\\520.jpg", 16)

The width is reduced to 80 % to exclude watermarks and the “Tencent Video” logo.

Combining the Slices into a GIF

After obtaining the 16 PNG files, they are merged into an animated GIF using the duration parameter of Image.save().

import argparse
from PIL import Image
import os

class SplitLongPicture:
    def __init__(self):
        self.dirName = os.path.split(os.path.abspath(__file__))[0]
        self.ImagePath = args.ImagePath
        self.SplitTimes = args.SplitTimes
        self.SwitchingTime = args.SwitchingTime
        self.Path, self.File = os.path.split(self.ImagePath)
        self.Image = self.check_image_file()
        self.pictureList = []

    def check_image_file(self):
        _imageType = ['.jpg', '.png', '.bmp']
        if not os.path.isfile(self.ImagePath):
            raise IOError("Please check the image path", self.ImagePath)
        elif os.path.splitext(self.File)[1].lower() not in _imageType:
            raise TypeError("Please select a supported image type", _imageType)
        else:
            return Image.open(self.ImagePath)

    def split_image(self):
        os.chdir(self.Path)
        try:
            os.makedirs('pictures')
        except FileExistsError:
            pass
        width, height = self.Image.size
        _unitHeight = height / self.SplitTimes
        for pictureNumber in range(self.SplitTimes):
            _cropBox = (0, _unitHeight * pictureNumber, width * 0.8, _unitHeight * (pictureNumber + 1))
            _unitPicture = self.Image.crop(_cropBox)
            _pictureName = os.path.join(self.Path, 'pictures', "%d.png" % pictureNumber)
            self.pictureList.append(_pictureName)
            _unitPicture.save(_pictureName)

    def composite_gif(self):
        images = []
        im = Image.open(self.pictureList[0])
        for file in self.pictureList[1:]:
            images.append(Image.open(file))
        gifName = os.path.join(self.Path, "result.gif")
        im.save(gifName, save_all=True, loop=True, append_images=images, duration=self.SwitchingTime * 1000)

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-p', '--ImagePath', help="Path to the image to split")
    parser.add_argument('-t', '--SplitTimes', type=int, help="Number of slices")
    parser.add_argument('-s', '--SwitchingTime', type=float, help="Frame duration in seconds")
    args = parser.parse_args()
    if None in args.__dict__.values():
        parser.print_help()
    else:
        Main = SplitLongPicture()
        Main.split_image()
        Main.composite_gif()

Run the script with:

python D:\SplitLongPicture.py -p C:\Users\Administrator\Downloads\520.jpg -t 16 -s 1.25

The resulting result.gif animates the original long image, providing a more engaging way to view the content.