How to make a randomizing avatar?

[HyperfixationStation]

Okay, please tell me if I should post this somewhere else, because i've been wondering this for a while and I was never sure where to put it.

I've seen a few avatars/signatures that include images and gifs that cycle between themselves when they refresh. I was wondering if there was some site or way to make it so it could do that? Once again, if there's some specific space I should put it on or something, please tell me. Thanks!

[Celozon]

There are probably other sites out there for this, but I've always used this one;
https://sig.grumpybumpers.com/

[HyperfixationStation]

Thanks a lot! <3