Active Social has the ability to randomly assign new members with a default profile picture in the event one hasn't been uploaded by the member.  Administrators have two options to choose from as Active Social 1.7.  Additional options will be added in future releases.

Option	Description
Default Generic Image	The default profile picture icon will displayed for all users that have not uploaded their own profile picture.  The default profile picture icon is named "profile.png" and is located in the DesktopModules/ActiveSocial directory.
Random Assignment	During the account creation process, if a user decides not to upload a profile picture they will be assigned one at random from the DesktopModules/ActiveSocial/images/avatars directory.  This process only occurs for new accounts or when a user without a profile picture updates their profile.  Active Social includes 7 sample avatars in different colors.  Administrators can add additional avatars to this directory at any time.  Make sure the files are "PNG" files and are at least 72 pixels high and 72 pixels wide.