Try going here and
here, upload your animation as a saved GIF file. Then when you upload it should say a few things, copy the text that has the

on them. And then you can copy it, paste it on quick reply or something, and then your done.
If you have an animation thats on a website, you can copy and paste the URL, and just paste it in quick reply. Which will show the link so people can click it and view your animation.
Another thing you could do is copy and past the URL, click 'Reply', the click the button that has a mountain on it, and then paste your URL. One thing you should make sure that it dosent have two 'http://' or the link will be bad.