Bucket :
Yes, you can host it at that site, then use that URL and post that BBCode in a Reply to have the image only in that one post, or if you want that as your sig, you goto edit your profile and add that BBCode in your signature area.
Thirteen :
Unfortunately, Geocities|Angelfire and sites like that dont allow direct linking. So the image wouldnt show up. You can try
http://www.tribes-hosting.com . thats where i am hosting mine.
Good luck fellas.