var images_ary=new Array(
'img_common/left_info_o.gif',
'mg_common/left_about_o.gif',
'img_common/left_phil_o.gif',
'mg_common/left_env_o.gif',
'img_common/left_work_o.gif',
'img_common/left_career_o.gif',
'mg_common/arrow_lg_o.gif'
);

function preLoad(imgAry) {
  var imgMax=imgAry.length;
  var images=new Array(imgMax);
  for (var i=0; i<imgMax; i++) {
    images[i]=new Image();
    images[i].src=imgAry[i];
  }
}