var updateGallery = (function(){
    var images = $('#main .gallery img').toArray();
    var currentImage = null;
    if (images.length > 0){
        currentImage = images[0];
    }    
    return function(){
        $(currentImage).fadeOut(1000);
        var newImage = images.pop();
        $(newImage).fadeIn(1000, function(){
            images.unshift(newImage);
            currentImage = newImage;
        });
        setTimeout(updateGallery, 5000);
    }
}());
setTimeout(updateGallery, 5000);