$HTTP["url"] =~ "^/images/2010" {
        expire.url = ( "" => "access 15 minutes" )
}

$HTTP["host"] =~ "(img1|img2|img3)\.example\.com" {
    expire.url = ( "" => "access 15 minutes" )
    setenv.add-response-header  = ("Cache-Control" =>"s-maxage=3600")
}