var imgsrc = src.substring(src.lastIndexOf("/")+1);


    /*var _Img = ["img4.jpg","img5.jpg","img7.jpg"];
    var i;
    for (i = 0; i < _Img.length; i++) {

   document.getElementById("img").src = _Img[i];
    }

    */


    switch (imgsrc)
    {
        case "img1.jpg": document.getElementById("img").src = "img2.jpg";
        break;
        case "img2.jpg": document.getElementById("img").src = "img3.jpg";
        break;
        case "img3.jpg": document.getElementById("img").src = "img4.jpg";
        break;
        case "img4.jpg": document.getElementById("img").src = "img5.jpg";
        break;
        case "img5.jpg": document.getElementById("img").src = "img6.jpg";
        break;
        case "img6.jpg": document.getElementById("img").src = "img7.jpg";
        break;
        case "img7.jpg": document.getElementById("img").src = "img8.jpg";
        break;
        case "img8.jpg": document.getElementById("img").src = "img9.jpg";
        break;
        case "img9.jpg": document.getElementById("img").src = "img10.jpg";
        break;
        case "img10.jpg": document.getElementById("img").src = "img11.jpg";
        break;
        case "img11.jpg": document.getElementById("img").src = "img12.jpg";
        break;
        case "img12.jpg": document.getElementById("img").src = "img1.jpg";
        break;

    }