You need toriprime or VIP to put pictures in your signature.
http://forum.toribash.com/tori_boosters.php
Here is a good explanation of both Toriprime and VIP:
http://forum.toribash.com/showthread.php?t=204885
Buying Forum Subscriptions with TC
You can buy ToriPrime for 750,000,000 TC.
You can buy VIP for 10,000,000,000 TC.