$(document).ready(function(){
  $('#banner-main a > img').each(function(){
    var curname = $(this).attr('src');
    var hovname = get_hov_name(curname);
    $(this).attr('hov', hovname).attr('nohov', curname)
           .mouseover(function(){$(this).attr('src', $(this).attr('hov'));})
           .mouseout(function(){$(this).attr('src', $(this).attr('nohov'));})
  });
});

function get_hov_name(curname)
  {
    var pos = curname.search(/_/);
    var len = curname.length;
    return curname.slice(0,pos)+'-hover'+curname.slice(pos,len);
  }