It is impossible to not notice that on many blogs some commentators have a photo and others don’t. You may think that the respective authors have users registered on that blog. That is not true, the current version of wordpress don’t support author photo.

They have photos on their comments because they use gravatar service. Gravatar allows you to make an account with your e-mail address and you can upload a photo. When you post a comment to a blog that have avatars enabled, the respective blog will try to get the photo from Gravatar. Cool, huh ?

If you change your photo it will be changed on all blogs you commented on.

So, go to http://www.gravatar.com and build your profile now. Comment on this blog post to test if your photo is showing.