Its pretty simple you can see my signature for proof that it works. Just refresh the page and see my signature change.
Ok so for this tutorial follow these steps.
1. Go to this website
3. Once you sign in, just import the URL's (up to 3) of the Images you would like to be in your Sig / Avatar
4. When your done click "Edit Sigs" or "Edit Avatars" depending on which one you made
5. Get the URL at the top
6. You now have your changing signature or avatar.