An avatar is an image that represents you online. We use the widely-used Gravatar service to fetch public avatars for you and your correspondents.
You can upload and manage your own avatar on the Gravatar website, at https://en.gravatar.com. A different avatar can be set for each email address you use. Many email clients, including FastMail, will display these images next to the emails you send. We also show your avatar in the top left corner of the screen when you are logged in.
If you'd rather not see other people's avatars show up throughout your mail, you can turn the avatar system off.