$(document).ready(function(){
$(".box_details_container").hide();
$(".box_head").toggle(function(){
$(this).next(".box_details_container").slideDown(300);
var t = $(this).find(".cross");
t.css('background-image','url(images/hide.gif)');


}, function(){
$(this).next(".box_details_container").slideUp(300);
var t = $(this).find(".cross");
t.css('background-image','url(images/expand.gif)');
 });
});