var revert = new Array();
var inames = new Array('i_lArrow','i_rArrow','s_huntelaar','s_drawing_wall','s_aig','s_btn_mag','s_digitalDesigner','s_jungle','s_national_gallery','s_tate','s_nissan');

// Preload
if (document.images) {
  var flipped = new Array();
  for(i=0; i< inames.length; i++) {
    flipped[i] = new Image();
    flipped[i].src ="images/"+inames[i]+"_o.jpg";
  }
}

function over(num) {
  if(document.images) {
    revert[num] = document.images[inames[num]].src;
    document.images[inames[num]].src = flipped[num].src;
  }
}
function out(num) {
  if(document.images) document.images[inames[num]].src = revert[num];
}