var PreloadImage = new Image();
PreloadImage.src = '/img/hotel-winter.jpg';

$(document).ready(function() {
    setInterval(function()
    {
        var imageSrc = '/img/hotel-winter.jpg';
        var oldSrc = $('img#hotel').attr('src');
        if (oldSrc.match(/hotel-winter\.jpg/)) {
            imageSrc = '/img/hotel-sommer.jpg';
        }
    
        $('img#hotel')
            .attr('src', imageSrc)
            .css('margin-left', '6px')
            .css('margin-bottom', '5px')
            .fadeIn(3000, function() {
                $(this).css('margin-left', '');
                $(this).css('margin-bottom', '');
            });
    }, 5*1000);
});