It is called an Avi (avatar) or DP (display picture.)
Profile pictures on Twitter are usually refered to as 'icons', although there is no official name for them.
The Avi on Twitter is your profile picture (Avitar).
if you do not have a picture on twitter that is what comes up as your profile pic.
Its basically your twitter "profile picture"
Clicking on the picture on their profile will open a larger version unless their profile is protected.
You go to edit profile, click browse and choose a picture from your computer .
Go to settings>Profile and change the profile pic.
@justinbieber
You click on upload a picture!
You must link it to Google or Twitter or Facebook and then Answers.com uses your Profile Picture.
You need a picture with a .gif format. And it has to be animated.
Save a gif to your computer and upload it as your profile picture on Twitter.