settings file missing explanation for CIVICRM_IMAGE_UPLOADURL variable

The settings file does not provide an explation/ example for the variable CIVICRM_IMAGE_UPLOADURL
If someone can email me a correct sample, I can put together some explanitory text.

/**

• File system paths for this install:
  *
• $civicrm_root is the file system path on your server where the civicrm
• code is installed.
  *
• CIVICRM_TEMPLATE_COMPILEDIR is the file system path where compiled templates are stored.
  *
• CIVICRM_UPLOADDIR is the file system path to which CiviCRM files are uploaded.
  *
• EXAMPLE - CivicSpace / Drupal:
• If the path to the CivicSpace or Drupal home directory is /var/www/htdocs/civicspace
• the $civicrm_root setting would be:
• $civicrm_root = '/var/www/htdocs/civicspace/modules/civicrm';
  *
• the CIVICRM_TEMPLATE_COMPILEDIR would be:
• define( 'CIVICRM_TEMPLATE_COMPILEDIR', '/var/www/htdocs/civicspace/files/civicrm/templates_c' );
  *
• and the CIVICRM_UPLOADDIR would be:
• define( 'CIVICRM_UPLOADDIR', '/var/www/htdocs/civicspace/files/civicrm/upload' );
  *
• the CIVICRM_IMAGE_UPLOADDIR would be:
• define( 'CIVICRM_IMAGE_UPLOADDIR', '/var/www/htdocs/civicspace/files/civicrm/' );
  *
• EXAMPLE - Mambo:
• If the path to the Mambo home directory is /var/www/htdocs/mambo
• the $civicrm_root setting would be:
• $civicrm_root = '/var/www/htdocs/mambo/administrator/components/com_civicrm/civicrm';
  *
• the CIVICRM_TEMPLATE_COMPILEDIR would be:
• define( 'CIVICRM_TEMPLATE_COMPILEDIR', '/var/www/htdocs/mambo/media/civicrm/templates_c' );
  *
• and the CIVICRM_UPLOADDIR would be:
• define( 'CIVICRM_UPLOADDIR', '/var/www/htdocs/mambo/media/civicrm/upload' );
• Please make sure that the COMPILERDIR and UPLOADDIR are created and the
• web server user has write access to that directory
  *
  */
  global $civicrm_root;
  $civicrm_root = '';
  define( 'CIVICRM_TEMPLATE_COMPILEDIR', '' );
  define( 'CIVICRM_UPLOADDIR' , '' );
  define( 'CIVICRM_IMAGE_UPLOADDIR' , '');
  define( 'CIVICRM_IMAGE_UPLOADURL' , '' );