quick and dirty preloading

gistfile1.js

var preloadImages = [
        'path/to/image1.png',
        'path/to/image2.png',
        'path/to/image3.png'
    ],
    
    toLoad = 0,
    
    preload = function () {
        var i = preloadImages.length;
        
        toLoad += i;
        
        while (i--) {
            setTimeout((function (i) {
                return function () {
                    var img = new Image();
                    img.onload = onload;
                    img.src = preloadImages[i];
                };
            }(i)), 1);
        }
    },
    
    onload = function () {
        toLoad--;
        
        if (toLoad === 0) {
            // everything is loaded!
        }
    };