Advanced Maintenance

[AMP Admin]

I see lots of maintenance page solutions but I would like to keep serving
images and a few directories.  Is that possible?

Right now we have:
	if (-f $document_root/maintenance.php) {
		rewrite  ^(.*)$  /maintenance.php last;
		break;
	}

But we would like to make the privacypolicy.php page and the images & promo
directories always available.  That way people can always see our
advertisers, images, and privacy policy.