Click on your username in the bar at the top [it has "Inbox" "Alerts" and "Log Out" beside it], in the drop-down, click on "Avatar" and choose a file from your computer. It also allows you to use Gravatar if you have an account.
Click on your username in the bar at the top [it has "Inbox" "Alerts" and "Log Out" beside it], in the drop-down, click on "Avatar" and choose a file from your computer. It also allows you to use Gravatar if you have an account.