Click on Select File and choose a picture from your computer
In the selection window click Open
Now you will be redirected to the Forum page, just press the yellow button Upload to complete the process.
From a mobile device:
Tap Menu in the top right corner of the screen
Tap your Avatar picture
Tap My Account
Now, in the various tabs, tap Avatars
Upload a new picture
Press Upload to save the change.
Note: if you had already uploaded a picture, it will be shown into the avatar pool and you can use it again. If you want to permanently remove it from you avatar history, just click on the blue Delete button below each picture.
Users are not allowed to use the Amazon Mark as their Avatar picture.