Photos in Digest
The digest version can display photos for each person that has posted a message to the list. These photos are pulled from Gravatar, a free service that is used mainly by bloggers.
The photo is useful for helping to remember people they have met at off line conferences, etc.
The digest with photos looks like this
Anybody can upload their photo or avatar at Gravatar for free.
Simply surf to http://Gravatar.com and click on blue button to start the signup process.
When you get your confirmation email, click on the link.
And follow their directions to upload your photo or avatar. When the next digest is sent out, your photo will be displayed alongside your email address.