<?PHP
$file = 'test20110429150342063.jpg';
$a = GETIMAGESIZE($file);
$bpc = ISSET($a['bits']) ? $a['bits'] : 8;
//Read whole file
$f = FOPEN($file,'rb');
$data = '';
WHILE(!FEOF($f)) {
$data .= FREAD($f,4096);
}
FCLOSE($f);
$dpi = UNPACK('x14/ndpi', $data);
print_r($dpi);
?>