function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

function changeImages() {
  if (document.images && (preloadFlag == true)) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
    }
  }
}

var preloadFlag = false;
function preloadImages() {
  if (document.images) {
    navi_01_navi_02_over = newImage("images_left/navi_01_navi_02_over.gif");
    navi_02_over = newImage("images_left/navi_02_over.gif");
    navi_03_navi_02_over = newImage("images_left/navi_03_navi_02_over.gif");
    navi_03_navi_04_over = newImage("images_left/navi_03_navi_04_over.gif");
    navi_04_over = newImage("images_left/navi_04_over.gif");
    navi_05_navi_04_over = newImage("images_left/navi_05_navi_04_over.gif");
    navi_06_navi_04_over = newImage("images_left/navi_06_navi_04_over.gif");
    navi_06_over = newImage("images_left/navi_06_over.gif");
    navi_06_navi_08_over = newImage("images_left/navi_06_navi_08_over.gif");
    navi_07_navi_08_over = newImage("images_left/navi_07_navi_08_over.gif");
    navi_08_over = newImage("images_left/navi_08_over.gif");
    navi_09_navi_08_over = newImage("images_left/navi_09_navi_08_over.gif");
    navi_10_over = newImage("images_left/navi_10_over.gif");
    navi_10_navi_08_over = newImage("images_left/navi_10_navi_08_over.gif");
    navi_11_over = newImage("images_left/navi_11_over.gif");
    navi_12_over = newImage("images_left/navi_12_over.gif");
    navi_13_over = newImage("images_left/navi_13_over.gif");
    navi_14_over = newImage("images_left/navi_14_over.gif");
    navi_15_over = newImage("images_left/navi_15_over.gif");
    navi_16_over = newImage("images_left/navi_16_over.gif");
    navi_17_navi_19_over = newImage("images_left/navi_17_navi_19_over.gif");
    navi_17_over = newImage("images_left/navi_17_over.gif");
    navi_18_navi_19_over = newImage("images_left/navi_18_navi_19_over.gif");
    navi_19_over = newImage("images_left/navi_19_over.gif");
    navi_20_navi_19_over = newImage("images_left/navi_20_navi_19_over.gif");
    navi_21_navi_19_over = newImage("images_left/navi_21_navi_19_over.gif");
    navi_21_over = newImage("images_left/navi_21_over.gif");
    navi_22_over = newImage("images_left/navi_22_over.gif");
    navi_23_over = newImage("images_left/navi_23_over.gif");
    navi_24_navi_26_over = newImage("images_left/navi_24_navi_26_over.gif");
    navi_24_over = newImage("images_left/navi_24_over.gif");
    navi_25_navi_26_over = newImage("images_left/navi_25_navi_26_over.gif");
    navi_26_over = newImage("images_left/navi_26_over.gif");
    navi_27_navi_26_over = newImage("images_left/navi_27_navi_26_over.gif");
    navi_28_navi_26_over = newImage("images_left/navi_28_navi_26_over.gif");
    navi_28_over = newImage("images_left/navi_28_over.gif");
    navi_29_over = newImage("images_left/navi_29_over.gif");
    navi_30_over = newImage("images_left/navi_30_over.gif");
    navi_31_over = newImage("images_left/navi_31_over.gif");
    navi_33_over = newImage("images_left/navi_33_over.gif");
    navi_35_over = newImage("images_left/navi_35_over.gif");
    preloadFlag = true;
  }
}