$(document).ready(function() {

var images_count = $('div#post_it img').size();


 var count = 0;
 var idinterval;
 function slideshow() {
     
    
    
    if(count>=images_count){
        $('div#post_it img:nth-child('+images_count+')').hide();
        $('div#post_it img:nth-child(1)').show();
       
        count=1;
    } else {
        $('div#post_it img:nth-child('+count+')').hide();
        count++;
        $('div#post_it img:nth-child('+count+')').show();
    }
    
    
 }
 idinterval = setInterval(slideshow, 3000);

});