One thing you can do - I did it - is go into the "User CP" and under "Networking" click on "Pictures and Albums", then click on "Add Album", the you can upload a picture from your computer. If I missed something, please let me know!
Oh, a siggy (or signature) is something you can set in your profile...explore the User CP and you'll find it. An avatar is the picture that shows up under your username when you post on a thread. Look at the pictures on the other poster's posts...that's what it looks like/what and avatar is. Hope this helps!!
"Horses are proof that God wants us to enjoy life"
SAVE THE MUSTANGS!!!!