Hey, what you do is you go onto the User CP button which is in the blue banner under where your name and notification bar is....
Then on the left hand side there is an option list, and under Settings & Options there is an option to edit your signature...
Once on there you can write in your pets OR you can add a picture.. to add a picture just follow this advice....
that should work for you
1.0.0 Red Amelanistic Corn - Diablo
0.1.0 Okatee Corn - Akeyra
0.1.0 Anerythristic Corn - Seraphis
1.0.0 Normal Royal Python - Kirby
1.0.0 Crested Gecko - Roger