Reverse a GIF with Python: Full Tutorial and Code Samples

Recently I saw a forum question about generating GIF animations with Python. Inspired by the answers, I tried reversing a GIF by reading its frames, reversing the order, and saving a new GIF.

Below are the results:

Code example using Pillow:

<code># encoding: utf-8
from PIL import Image, ImageSequence

# Open GIF
im = Image.open("nba.gif")
# Iterate frames and save each as PNG
index = 1
for frame in ImageSequence.Iterator(im):
    print("image %d: mode %s, size %s" % (index, frame.mode, frame.size))
    frame.save("./images/frame%d.png" % index)
    index += 1

# Collect frames
imgs = [frame.copy() for frame in ImageSequence.Iterator(im)]
# Reverse frames
imgs.reverse()
# Save reversed GIF
imgs[0].save('./reverse_out.gif', save_all=True, append_images=imgs[1:])
</code>

A minimal version:

<code># encoding: utf-8
from PIL import Image, ImageSequence

im = Image.open(r'./nba.gif')
sequence = []
for f in ImageSequence.Iterator(im):
    sequence.append(f.copy())
sequence.reverse()
sequence[0].save(r'./r-nba.gif', save_all=True, append_images=sequence[1:])
</code>

Generating a GIF from multiple static images with imageio:

<code># coding=utf8
import imageio, os

path = '../images'
filenames = [os.path.join(path, f) for f in os.listdir(path)
             if f.lower().endswith(('jpg', 'jpeg', 'png'))]

images = [imageio.imread(fn) for fn in filenames]
imageio.mimsave('movie.gif', images, duration=0.3)
</code>

More flexible approach using imageio writer:

<code>import imageio

with imageio.get_writer('/path/to/movie.gif', mode='I') as writer:
    for filename in filenames:
        image = imageio.imread(filename)
        writer.append_data(image)
</code>

Using imageio is recommended over the older image2gif package.