Avatars are unlockable profile pictures for your account! To change your avatar, you want to go to any mine, then tap the icon in the top right corner that shows two grey people (to the left of the cog). At the bottom you want to select "Your Profile" (second icon from the left showing a person with a pencil). You'll be able to select your profile picture from there!
What is an Avatar? How do I change my Avatar?
Last Updated: 456d