I don't understand the problem here. The original file is in GIF format (it downloads that way for me, anyway), and there are other emoji GIF files that are about as large. Here's a copy that I downloaded. I've also attached a re-encoded copy, in case there's some metadata voodoo that is causing issues.
I'm not sure if attached files animate automatically, I'll see if I can edit this post to point to its own attachments.
ETA: Well, even the attachments don't seem to be working. If I upload the file, then download it again, the filesize drops to 97k. I guess the forum software is doing some "sanitization", and only keeping the first frame.