Also, you can use the Giphy too if you want to add GIF because if you are trying to use the imgur for uploading some GIF and try to make a preview right here on our forum it doesn't support it just gives you an error code or an invalid syntax. With the use, if Giphy they have BBcode supported too but AFAIK you must need to create an account and I think it's not hard. I hope I give you some information too.