I'll explain the best I can.
First things first, you have to have a website somewhere. Just signup for one of those free website somewhere who offers it. All you have to do is do a search on "free webspace" - you will get some hits, then signup. You'll be given an access to your free webspace area (usually password protected, but something you can control, of course). From here you should get some "tools" to use and one of them should be to "manage your files" - should be an upload utility there for you to upload some image files from your computer to your library in your free webspace. Once uploaded, if you click on one of them, it should produce a URL (http://yourfreewebspaceacct.com/yourimage.gif for example). This would be the URL that your are going to code on the UBB - use the IMG tags then enclose the URL of the image. this is coding you'll write on your signature block in your profile or on your posts.
I hope this helps a little. <IMG SRC="smilies/biggrin.gif" border="0">
[ November 05, 2001: Message edited by: evasyar ]