I’ve done this a couple of times and it’s actually much easier than I expected. If you just want a simple GIF from a sequence of pictures, you don’t really need anything complicated — most GIF makers let you upload the images, arrange them in order, adjust how long each frame stays on screen, and export it.
The frame timing makes a bigger difference than I expected. If everything changes too quickly, it looks more like a slideshow than a GIF. I usually slow the frames down a little first, then speed them up until the movement feels natural.
For group chats, I’d also keep the final file fairly small so it doesn’t take forever to send.