Allora, una regola importante è che le immagini grandi siano tutte di uguale dimensione.
Io, nel mio esempio, al posto di reperire i path delle immagini da un db, ho utilizzato un array, ma non dovrebbe essere difficile modificare il codice in modo da adattarlo al db.
codice:
<%@LANGUAGE="VBSCRIPT" CODEPAGE="1252"%>
<%
pathSmallImages = "/img/small/"
pathBigImages = "/img/big/"
dim arrImages(2)
arrImages(0) = "foto(505).jpg"
arrImages(1) = "foto(506).jpg"
arrImages(2) = "foto(507).jpg"
for i = 0 to uBound(arrImages)
strPreload = strPreload & pathBigImages & arrImages(i) & "'"
if i < uBound(arrImages) then strPreload = strPreload & ","
next
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Documento senza titolo</title>
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_swapImgRestore() { //v3.0
var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}
function MM_preloadImages() { //v3.0
var d=document; if(d.images){ if(!d.MM_p) d.MM_p=new Array();
var i,j=d.MM_p.length,a=MM_preloadImages.arguments; for(i=0; i<a.length; i++)
if (a[i].indexOf("#")!=0){ d.MM_p[j]=new Image; d.MM_p[j++].src=a[i];}}
}
function MM_findObj(n, d) { //v4.01
var p,i,x; if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function MM_swapImage() { //v3.0
var i,j=0,x,a=MM_swapImage.arguments; document.MM_sr=new Array; for(i=0;i<(a.length-2);i+=3)
if ((x=MM_findObj(a[i]))!=null){document.MM_sr[j++]=x; if(!x.oSrc) x.oSrc=x.src; x.src=a[i+2];}
}
//-->
</script>
</head>
<body onLoad="MM_preloadImages(<%=strPreload%>)">
<center><%
for i = 0 to uBound(arrImages)
%>
<%=arrImages(i)%>',1)">[img]<%=pathSmallImages%><%=arrImages(i)%>[/img]
<%
next
%>
[img]<%=pathBigImages%><%=arrImages(0)%>[/img]
</center>
</body>
</html>