Use Gravatar for the user's picture

Currently, AFAIK, the user's picture url is only provided when logged using a Google account.

Avatar can also be fetched using Gravatar, which provides a way to add information about oneself based on the email, especially the avatar. I see two non-exclusive possibilities:

• by doing that automatically on the first log in, if the profile associated to the email exists in gravatar;
• by offering a button which sets the avatar URL using Gravatar, in the Profile Settings page;

That seems reasonably difficult, especially for newcomers, as the users table already stores the picture url, and Grist already display the avatar if provided. What do you think?

Resources:

• UserAPI