How to send an avatar in an email?

Question

gmail

Where can I read more about how to format email headers?

For example, modern mail services allow you to attach autarchies to messages and other meta-data.

As I understand it, data such as the avatar of the message, etc., is transmitted through headers.
Can you tell me where I can read more about this? Or at least what kind of standard is this?

Answer 1

For mail.ru, you can put avatars here for a box from the domain https://postmaster.mail.ru/
And so, put on https://ru.gravatar.com/ - in a couple of days the main mailers will be pulled up. But not all. And not necessarily.

Answer 2

There are no such standards in the mail. Such features can be in separate email clients or web services. But from the point of view of the mail protocol, there are no such standards, and this will not work between different clients.

Answer 3

There is a BIMI standard for the domain logo , but not many places support it.