Click "Your User Name" on the Main Menu Bar -- at the top of the page -- on the right. A drop-down of options will open look down the list for 'Avatar' click it and follow the instructions. You can upload one from your PC or you can Use Gravatar if you have one setup with them already. Note: If you don't know what Gravatar is then you don't have one, Google is now your best friend to help you find out what it is. Note: The maximum size accepted for a custom avatar is 120 by 120 pixels or 127.0 KB (whichever is smaller).