If you have the scene downloaded to your computer as an MP4 or similar video file, you should be able to use this site to create a GIF of the moment you want.
That's the site I use to make all of the GIFs I upload here on the wiki. Just make sure that your video file is less than 100 MB, because EZGIF can't take anything bigger than that. And make sure that the GIF you make and upload here to the wiki is less than 8 MB in size, because anything bigger won't upload properly.