// create a new array and assign images to 6 elements
var pix = new Array;
pix[0] = "images/rotate/waterstone-mini.jpg";
pix[1] = "images/rotate/Sardis_Optical-mini.jpg";
pix[2] = "images/rotate/A&D-mini.jpg";
pix[3] = "images/rotate/waterstone-mini.jpg";
pix[4] = "images/rotate/logo_bcgov-mini.jpg";
pix[5] = "images/rotate/bigo-mini.jpg";
pix[6] = "images/rotate/mikedellafortuna-mini.jpg";

// get a random integer between 0 and 5
var rand = Math.floor(Math.random() * 7);

// assign random image to the HTML <img> tag of pic id 
document.getElementById("pic2").src = pix[ rand ];