var numImages = 60;
var totalImages = 80;
var imageOrder = new Array();

for (i = 0; i < totalImages; i++) {
    imageOrder[i] = i + 1;
}

imageOrder.sort(function() { return.5 - Math.random() });

placeImages();

function placeImages() {
    for (i = 0; i < numImages; i++) {
        document.write("<div id='" + i + "' style='position:absolute\;'><img src='img/obj" + imageOrder[i] + ".png'></div>");
        var curr = document.getElementById(i);
        curr.style.top = Math.floor(Math.random() * window.innerHeight - 25);
        curr.style.left = Math.floor(Math.random() * window.innerWidth - 25);
    }
}