var buttons = new Array(
	new Array('/img/b_home.gif','/img/b_home_over.gif'),
	new Array('/img/b_videos.gif','/img/b_videos_over.gif'),
	new Array('/img/b_equip.gif','/img/b_equip_over.gif'),
	new Array('/img/b_train.gif','/img/b_train_over.gif'),
	new Array('/img/b_resume.gif','/img/b_resume_over.gif')
);

var pImg;

function getObj(oid) {
  if (document.all && document.all(oid))
     return document.all(oid);
  else if (document.getElementById && getElementById(oid))
     return getElementById(oid);
  else return;
}

function preloadImg() {
	for (i=0; i < buttons.length; i++)
	  for (j=0; j < buttons[i].length; j++)
	    setImage(buttons[i][j]);
}

function setImage(isrc) {
   pImg = new Image();
   pImg.src = isrc;
}

function changeImg(bid,iid) {
  var oImg = getObj("b"+bid);
  oImg.src = buttons[bid][iid];
}