function preloadImagesFromDirectory(dir) {
 
    if(!dir) return;
 
    function getJSON(URL,success){
 
        // Create new function (within global namespace)
        // (With unique name):
        var uniqueID = 'json'+(+(new Date()));
            window[uniqueID] = function(data){
                success && success(data);
            };
 
        // Append new SCRIPT element to DOM:
        document.getElementsByTagName('body')[0].appendChild((function(){
            var script = document.createElement('script');
            script.type = 'text/javascript';
            script.src = URL.replace('callback=?','callback=' + uniqueID);
            return script;
        })());
 
    }
 
    function preload(srcArray) {
        for(var i = 0; i < srcArray.length; i++) {
            (new Image()).src = srcArray[i];
        }
    }
 
    // Get that JSON data:
    getJSON('scanImageDirectory.php?directory=' + encodeURIComponent(dir) + '&callback=?', function(data){
        return data.images ? preload( data.images ) : false;
    });
 
}