目前没有RFC。要验证您可以搜索现有的RFC，请访问： https://www.rfc-editor.org/retrieve/

此外，创建RFC的过程是不平凡的。但是，如果您在实验或信息类别中使用RFC，您可以考虑独立提交过程，详细信息如下： https://www.rfc-editor.org/about/independent/

AFAIK there is no RFC or other standard to retrieve an avatar (image/icon) from an email address.

I think this would be a great feature.

One possible solution:

Get avatar via DNS

1. user enters his email address.
2. The domain belonging to this email adress DNS gets asked: Avatar for "foo@example.com"
3. DNS replies: Get image from URL. For example: http://example.com/foo.png

Questions

• Is there already a RFC or other standard?
• Why is there no such standard yet?
• How to get it come true?

I know that Gravatar exists. But AFAIK it is not a standard.

Currently there is no RFC for this. To verify you can search the existing RFC's at: https://www.rfc-editor.org/retrieve/

Also, the process to create an RFC is non-trivial. However, if you are ok with an RFC in the experimental or informational category, you could consider the Independent Submission process which is detailed at: https://www.rfc-editor.org/about/independent/