I guess you know Gravatar? This service where you upload your profile picture and every platform that knows your mail address can use it to generate a link for an image?
There is a #FLOSS alternative around it's called #libravatar. It has been around for such a long time, that the original authors decided they got too old to do it. They decided to shutdown the service this year.
Now the #Fedora Community stepped in and will continue the service:
P.S.: It's federated ;)