how do sites automagically grab profile pictures?

Question

Some sites have the ability to grab your profile picture after you sign up for the first time without the user actually uploading a pic. I think stackoverflow has this functionality at sign as well....How does it work?

Answer 1

stackoverflow uses gravatars which are linked by your email address. You can read more about how gravatar works on their developer resources page.

Answer 2

It uses gravatar.com I believe. You associate an avatar with your email and then sites can use your email to locate your avatar. There is a plugin for Wordpress. Or google search 'gravatar API' to put it on your own site.

Good luck!

Answer 3

There is a site called http://gravatar.com that takes a MD5 hash of your email to load a profile picture

Answer 4

They're using OpenID. Some OpenID providers allow you to upload a profile picture or it wil associate it with your Gravatar's e-mail address (http://en.gravatar.com/).