var src = new Array (
'/img/contents/other/access/map.gif',
'/img/contents/other/access/osaka.gif',
'/img/contents/other/access/shin_osaka.gif',
'/img/contents/other/access/kyoto.gif',
'/img/contents/other/access/nara.gif',
'/img/contents/other/access/air_kansai.gif',
'/img/contents/other/access/air_itami.gif',
'/img/contents/other/access/gotenyama.gif'
);

var img = new Array ();
for (var i=0;i<src.length;i++) {
  img[i] = new Image ();
  img[i].src = src[i];
}

function swap (str) {
  document.getElementById('map_all').src = img[str].src;
}