var photonumber = 6;
var randomnumber = Math.random();
var randnumber = Math.round( (photonumber-1) * randomnumber) + 1;

photos = new Array;
photos[1] = "../media/image15.jpg";
photos[2] = "../media/image47.jpg";
photos[3] = "../media/image48.jpg";
photos[4] = "../media/image49.jpg";
photos[5] = "../media/image50.jpg";
photos[6] = "../media/image51.jpg";
var photo = photos[randnumber];