var obrazky1 = new Array("box1-photo-a.jpg", "box1-photo-b.jpg", "box1-photo-c.jpg", "box1-photo-d.jpg", "box1-photo-e.jpg", "box1-photo-f.jpg", "box1-photo-g.jpg", "box1-photo-h.jpg");
var obrazky2 = new Array("box2-photo-a.jpg", "box2-photo-b.jpg", "box2-photo-c.jpg");
var obrazky3 = new Array("box3-photo-a.jpg", "box3-photo-b.jpg", "box3-photo-c.jpg", "box3-photo-d.jpg", "box3-photo-e.jpg");
var obrazky4 = new Array("box4-photo-a.jpg", "box4-photo-b.jpg", "box4-photo-c.jpg", "box4-photo-d.jpg", "box4-photo-e.jpg", "box4-photo-f.jpg", "box4-photo-g.jpg", "box4-photo-h.jpg");


function StartRotate() {
      var prefix = '../_img/box/';
      document.getElementById('box1').src = prefix+obrazky1[Math.round(Math.random()*(obrazky1.length-1))];
      document.getElementById('box2').src = prefix+obrazky2[Math.round(Math.random()*(obrazky2.length-1))];
      document.getElementById('box3').src = prefix+obrazky3[Math.round(Math.random()*(obrazky3.length-1))];
      document.getElementById('box4').src = prefix+obrazky4[Math.round(Math.random()*(obrazky4.length-1))];
}