The question is in the subject line. Unfortunately I've forgotten where to do this!! I've looked around a bit but I can't locate where to do this. Help or links would be greatly appreciated. Thank you!

Peronal tab on top -> pets ->the “pet button” underneath the pet you want to change -> “change headshot” down at the very bottom

I’m not 100% certain this is what you’re looking for, but I think so

It's exactly what I'm looking for . Thanks so much!