var min = 3;
var max = 257;
var prefix = ""; // obsolete, as 'max' exceeds 999
var pad = "0";
var ext = ".gif";
var width = 473;
var height = 600;
function randomFileName() {
	var nr = Math.round(max * Math.random());
	// just to be sure
	if (nr < min) nr = min;
	else if (nr > max) nr = max;
	// pad the file name
	var f = prefix;
	var l = max.toString().length;
	for (var i = nr.toString().length; i < l; ++i)
		f += pad;
	f += nr;
	f += ext;
	return f;
}
function imageTag(fileName, w, h) {
	var t = "<img src=";
	t += '"';
	t += fileName;
	t += '"';
	if (w.toString().length > 0) {
		t += " width=";
		t += w;
	}
	if (h.toString().length > 0) {
		t += " height=";
		t += h;
	}
	t += " />";
	return t;	
}