faster way to display jpg-blobs?

Hello,

I'm new to this list.

And I have the following question: is there a better/faster way than the
following to read jpeg-blobs out of the database and display them?

if( $db->next_record() ){
header("Content-Type: image/jpeg");
$bild = $db->lo_read($db->f("oid"));
header("Content-Length: 1024000"); // has to be calculated
print($bild);
}

where lo_read() is

function lo_read($oid, $mode="r"){
$this->connect();
pg_exec($this->Link_ID, "begin"); // a must for blob-operations
if( $lo_id = pg_loopen( $this->Link_ID, $oid, $mode ) ){
$lo = pg_loread( $lo_id, 1024000 ); // has to be calculated
pg_loclose($lo_id);
}
pg_exec($this->Link_ID, "end");
return $lo; // empty leer, wenn auslesen gescheitert
}

Because of the begin/end every picture on a page is loaded one after the
other, I fear. Not simultaneous as if there would be a direct <img
src='pic_N.jpg'> instead of <img src='pic.php?id=N'>.

Using blobs is a must IMHO, as viewing the pics should only be possible for
authorized people.

Thanks, bye,
Knut