[Solved] Switching Images [closed]

The remainder operator is really useful for wrapping things like your index around:

index = (index + 1) % length

…where length is the length of what you’re indexing into (this assumes 0-based indexing).

So your Slide function can do something along these lines:

function Slide(car) {
    var urls = bs.url[car];
    var index = 0;

    function run() {
        Slider.css({
            "background": urls[index],
            "background-position": "center",
            "background-attachment" : "fixed",
            "background-size" : "cover"
        });
        index = (index + 1) % urls.length;
    }    

    run();
    setInterval(run, bs.time);
}