For permanent links you can use: https://ezgif.com/reverse?url=https://example.com/image.gif
Online GIF reverser
This tool allows you to easily and instantly reverse animated gifs.
It is also possible to make a GIF that runs in one direction and then reverses back to the start (ping-pong), for seamless looping.
Use GIF effects tool for more advanced options.
Upload an image by URL or select a file from your computer.
In addition to GIFs, this tool can reverse animated WebP, APNG, FLIF and MNG images. You can also use ezgif to reverse a video.