var effect = !Prototype.Browser.IE || getIEVersionNumber() > 6

var effects = Array();

function getIEVersionNumber() {
    var ua = navigator.userAgent;
    var MSIEOffset = ua.indexOf("MSIE ");

    if (MSIEOffset == -1) {
        return 0;
    } else {
        return parseFloat(ua.substring(MSIEOffset + 5, ua.indexOf(";", MSIEOffset)));
    }
};

function select_image(n) {
  if ($("img_"+n).visible()) return;
  effects.each(function(e){
    e.cancel();
  })
  $$(".img").each(function(e){
    if (e.visible()) {
      if (effect) {
        effects[0] = Effect.Fade(e, {duration: 0.5});
      }else{
        e.hide();
      }
    }
  })
  if (effect) {
    effects[1] = Effect.Appear($("img_"+n), {duration: 0.5});
  }else{
    $("img_"+n).show();
  }
  $$("#img_links a").each(function(e){
    e.removeClassName('selected')
  })
  $("link_"+n).addClassName('selected');
}