Field To Display Message
You can use Markup module using which you can add text or HTML which will display a picture..

Project page says


  This module adds the ability for site admins to add "Markup" widgets
  to the form. These essentially let designers of cck content-types
  insert additional markup into the node/edit form to display to
  content-authors. This is the equivalent of adding additional elements
  to $form of the type '#markup'.