In this tutorial i am going to show you how to change images dynamic on each time you refresh your page.

Demo

There is simple PHP script to get it working.

srand( microtime() * 1000000 );
$num = rand(1,2);
switch($num)
{
     case 1: 
     $imageName = "image1.jpg";
     break;
     case 2: 
     $imageName = "image2.jpg";
     break;
}

echo "<img src=images/".$imageName." />";