Avatars are small pictures on Bungie.net that serve to quickly identify particular users. Bungie.net users may select from nearly 100 avatars pre-approved by Bungie staff, their Halo 2 or Halo 3 emblem, or their Halo 3 player model as an avatar, for greater individuality. The default avatar displayed for all of those who have yet to choose an avatar
to display is an image of the webmaster with a black and blue background.
Those who would like to make an avatar and submit it for review can find useful information here