jQuery(document).ready(function(){
  window.setTimeout('nextpic()', 7000); // set duration here
});
function nextpic(){    
  if (jQuery("#currentpic").next().attr("href") == undefined){
    jQuery("#currentpic").attr("style", "display:none;");
    jQuery("#currentpic").attr("id", "");
    jQuery("#imageblock a:first").attr("id","currentpic");
    jQuery("#currentpic").attr("style", "");
  }
  else{
    jQuery("#currentpic").next().attr("id", "next");
    jQuery("#currentpic").attr("style", "display:none;");
    jQuery("#currentpic").attr("id", "");        
    jQuery("#next").attr("id", "currentpic");
    jQuery("#currentpic").attr("style", "");
  }
  window.setTimeout('nextpic()', 7000);  // and set duration here
}