function preload(imgObj,imgSrc) 
{
   eval(imgObj+' = new Image()')
   eval(imgObj+'.src = "'+imgSrc+'"')
}

preload('reinventing_fr_on','/images/reinventing_fr_on.gif');
preload('reinventing_fr_off','/images/reinventing_fr_off.gif');

preload('maximizing_fr_on','/images/maximizing_fr_on.gif');
preload('maximizing_fr_off','/images/maximizing_fr_off.gif');

preload('ensuring_fr_on','/images/ensuring_fr_on.gif');
preload('ensuring_fr_off','/images/ensuring_fr_off.gif');

preload('north_def_fr_on','/images/north_def_fr_on.gif');
preload('north_def_fr_off','/images/north_def_fr_off.gif');

preload('dev_21_fr_on','/images/dev_21_fr_on.gif');
preload('dev_21_fr_off','/images/dev_21_fr_off.gif');

function img_toggle( imgName, mode ) 
{
   if( document.images ) 
   {
      document[ imgName ].src = eval( imgName + "_" + mode + ".src" );
   }
}