function changeimg(id){
	obj1=document.getElementById(id);
  obj2=document.getElementById((id+'Secundaria'));
           		
  if ((obj1.style.display=="") || (obj1.style.display=="none")){
  	obj1.style.display="block";
    obj2.style.display="none";
  }
  else{
   	obj1.style.display="none";
    obj2.style.display="block";
  }
}