It's a gold account feature, when you have a GA you can go to your pets and you have the option to "leash" one of them and add a little description
The option for your pet's headshot to appear beneath your HA is a gold account feature right now. It used to cost CSC, but is now a GA perk. See news article here. If you end up getting a gold account, it's under the pet options, the little pull down carrot next to your pet's hunger and happiness.
Oops, a little late to post. Sorry bout the double ping!
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