var fadeTime = 6000;
var fadeLength = 2000;

function fadeImage() {
    var next;
    if ($('.rotate:visible ~ .rotate:hidden').length > 0) {
        next = $('.rotate:visible ~ .rotate:hidden').eq(0);
    } else {
        next = $('.rotate').eq(0);
    }
    $('.rotate:visible').fadeOut(fadeLength);
    $(next).fadeIn(fadeLength);
}

$(function() {
    if ($('.rotate').length > 1) { 
        setInterval("fadeImage();", fadeTime);
    }
});