var fade_number = 0;
var img = new Image();
var imgs = new Array("1.png", "2.png", "3.png", "4.png", "5.png", "6.png", "7.png", "8.png", "9.png", "10.png", "11.png", "12.png");
$(document).ready(
    function() {
        img.id = "a";
        img.style["width"] = "auto";
        img.style["height"] = "auto";
        img.src = f + imgs[fade_number++];
        $("#con").append(img);
        img = $("#a");
        img.fadeOut(speed, fin);
    }
);
function fout() {
    img.fadeOut(speed, fin);
}
function fin() {
    if (fade_number >= imgs.length) {
        fade_number = 0;
    }
    $(this).attr({ "src": f + imgs[fade_number++] });
    img.fadeIn(speed, fout);
}