When creating a Contact in CRM, you may notice that an image has already been filled in for this contact. Raven doesn't store images for contacts itself but, rather, picks up an applicable image from Gravatar.
Raven will search Gravatar's database to see if a matching avatar has been created for the email address on file. Gravatar (or "Globally Recognized Avatar") is a service run by Automattic to populate avatars in WordPress and a number of other programs.
You can change your own Gravatar by logging into the Gravatar website.