var pics = 6,
    pic_prefix = 'pic',
    pic_path   = 'pic/m',
    pic_ext_act  = '_1.gif',
    pic_ext_pass = '.gif';
var img_cache = new Array(pics * 2);

var is_loaded=0;

function loaded() {
  var i, j;

  if (is_loaded)
    return true;
    
  is_loaded = 1;

  for (i = 1, j = 0; i <= pics; i++) {
    img_cache[j] = new Image();
    img_cache[j++].src = pic_path + i + pic_ext_pass;

    img_cache[j] = new Image();
    img_cache[j++].src = pic_path + i + pic_ext_act;
  }

  return true;
}

function hilite(img_no, state) {
  if (!is_loaded || !(document.images[pic_prefix + img_no]))
    return false;

  document.images[pic_prefix + img_no].src = img_cache[(img_no - 1)* 2 + state].src;
  return false;
}