e value describes a graphical representation of the
        containing object.  This property will typically be used to provide the
        URL to an image (e.g. JPEG, GIF or PNG) resource that can be displayed
        to the user.  Any given object might have multiple such visual
        representations -- multiple screenshots, for instance, or the same
        image at different resolutions. In Activity Streams 2.0, there are
        essentially three ways of describing such references.
      </p>

      