var photonumber = 22;
var randomnumber = Math.random();
var randnumber = Math.round( (photonumber-1) * randomnumber) + 1;

photos = new Array;
photos[1] = "media/image01.jpg";
photos[2] = "media/image02.jpg";
photos[3] = "media/image03.jpg";
photos[4] = "media/image04.jpg";
photos[5] = "media/image05.jpg";
photos[6] = "media/image06.jpg";
photos[7] = "media/image07.jpg";
photos[8] = "media/image08.jpg";
photos[9] = "media/image09.jpg";
photos[10] = "media/image10.jpg";
photos[11] = "media/image11.jpg";
photos[12] = "media/image12.jpg";
photos[13] = "media/image13.jpg";
photos[14] = "media/image14.jpg";
photos[15] = "media/image15.jpg";
photos[16] = "media/image16.jpg";
photos[17] = "media/image17.jpg";
photos[18] = "media/image18.jpg";
photos[19] = "media/image19.jpg";
photos[20] = "media/image20.jpg";
photos[21] = "media/image21.jpg";
photos[22] = "media/image22.jpg";
var photo = photos[randnumber];