Hola otra vez:
 
De tirar la toalla... nanai...  
  
Metí el script en tu página y modifiqué pocas cosillas (las que te apunté anteriormente) y puse una página de pruebas aquí: 
http://www.pepemolina.com/acaser/planosan.html 
... pero ten en cuenta que tienes que trabajarla tú mismo...  
  
He visto que algunas fotos (mapas) tienen distinto tamaño... te recomiendo que las hagas iguales. 
El código del popup quedó así:  
 Código PHP:
    <html>
<head>
<script>
var dibujos;
var nFilas = 5;
var nColumnas = 11;
function subir()    {
    if (actual > (nColumnas - 1))    {
        actual -= nColumnas;
        document.images.centro.src = dibujos[actual].src;
    }
}
 
function bajar()    {
    if (actual < ((nFilas - 1) * (nColumnas)))    {
        actual += nColumnas;
        document.images.centro.src = dibujos[actual].src;
    }
}
 
function izq()    {
    if ((actual % nColumnas) > 0)    {
        actual -= 1;
        document.images.centro.src = dibujos[actual].src;
    }
}
 
function der()    {
    if ((actual % nColumnas) < (nColumnas - 1))    {
        actual += 1;
        document.images.centro.src = dibujos[actual].src;
    }
}
 
function precarga()    {
    var imagenes = new Array(precarga.arguments.length)
    for (var i = 0; i < imagenes.length; i ++)    {
        imagenes[i] = new Image();
        imagenes[i].src = precarga.arguments[i];
    }
    return imagenes;
}
 
function ini()    {
    _dibujos = new Array(
            'http://webs.ono.com/usr028/turiscan/images/a1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/b1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/c1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/d1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/e1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e11.jpg'
    );
 
    actual = parseInt(location.search.split("=")[1]);
    document.images.centro.src = _dibujos[actual];
 
 
    dibujos = new precarga(
            'http://webs.ono.com/usr028/turiscan/images/a1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/a11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/b1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/b11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/c1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/c11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/d1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/d11.jpg',
 
            'http://webs.ono.com/usr028/turiscan/images/e1.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e2.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e3.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e4.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e5.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e6.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e7.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e8.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e9.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e10.jpg',
            'http://webs.ono.com/usr028/turiscan/images/e11.jpg'
 
    );
}
 
</script>
</head>
<body onload="ini()" style="margin: 0;">
 
<table border=1 >
    <tr>
        <td> </td>
        <td style="text-align: center" onclick="subir()"> ↑ </td>
        <td> </td>
    </tr>
 
    <tr>
        <td style="valign: middle" onclick="izq()" > ← </td>
        <td style="text-align: center"><img name="centro" src=""></td>
        <td style="valign: middle" onclick="der()" > → </td>
    </tr>
 
    <tr>
        <td> </td>
        <td style="text-align: center" onclick="bajar()" >↓ </td>
        <td> </td>
    </tr>
</table>
 
</body>
</html> 
   
  Fíjate que la precarga está detrás de la selección para que tarde menos en mostrarse el mapa actual... 
Se puede optimizar, pero "paciencia"... cuando te funcione veremos como mejorarlo. 
Saludos