$file = 'image.gif';
if (file_exists($file)) {
	header('Content-Description: File Transfer');
	header('Content-Type: application/octet-stream');
	header('Content-Disposition: attachment; filename='.basename($file));
	header('Content-Transfer-Encoding: binary');
	header('Expires: 0');
	header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
	header('Pragma: public');
	header('Content-Length: ' . filesize($file));
	ob_clean();
	flush();
	readfile($file);
	exit;
}

Príklad 2

// URL: blog.red-pill.cz/2007/03/06/zabezpecene-stahovani-souboru/
 
$file = basename($file);
$filepath = $download_folder.'/'.$file';
header('Pragma: public');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Cache-Control: private',false);
header('Content-Transfer-Encoding: binary');
header('Content-type: image/jpg'); // konkretny MIME-typ
header('Content-Disposition: attachment; filename='.$file);
readfile($filepath);

function main($dir, $item) {		// download file
	global $LANG,$CLIENT;
	
	if(!t3quixplorer_div::get_is_file($dir,$item)) t3quixplorer_div::showError($item.": ".$LANG->getLL("error.fileexist"));
	if(!t3quixplorer_div::get_show_item($dir, $item)) t3quixplorer_div::showError($item.": ".$LANG->getLL("error.accessfile"));
	
	$abs_item = t3quixplorer_div::get_abs_item($dir,$item);
	header('Content-Type: '.(($CLIENT["BROWSER"]=='msie' || $CLIENT["BROWSER"]=='opera')?'application/octetstream':'application/octet-stream'));
	header('Expires: '.gmdate('D, d M Y H:i:s').' GMT');
	header('Content-Transfer-Encoding: binary');
	header('Content-Length: '.filesize($abs_item));
	if($CLIENT["BROWSER"]=='msie') {
		header('Content-Disposition: inline; filename="'.$item.'"');
		header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
		header('Pragma: public');
	} else {
		header('Content-Disposition: attachment; filename="'.$item.'"');
		header('Cache-Control: no-cache, must-revalidate');
		header('Pragma: no-cache');
	}
	
	@readfile($abs_item);
	exit;
}

function download_item($dir, $item) {		// download file
	// Security Fix:
	$item=basename($item);

	if ((($GLOBALS["permissions"] & 01) != 01)
	&& (($GLOBALS["permissions"] & 16) != 16))
		show_error($GLOBALS["error_msg"]["accessfunc"] . $GLOBALS["permissions"]);
	
	if(!get_is_file($dir,$item)) show_error($item.": ".$GLOBALS["error_msg"]["fileexist"]);
	if(!get_show_item($dir, $item)) show_error($item.": ".$GLOBALS["error_msg"]["accessfile"]);
	
	$abs_item = get_abs_item($dir,$item);
	$browser=id_browser();
	header('Content-Type: '.(($browser=='IE' || $browser=='OPERA')?
		'application/octetstream':'application/octet-stream'));
	header('Expires: '.gmdate('D, d M Y H:i:s').' GMT');
	header('Content-Transfer-Encoding: binary');
	header('Content-Length: '.filesize($abs_item));
	if($browser=='IE') {
		header('Content-Disposition: attachment; filename="'.$item.'"');
		header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
		header('Pragma: public');
	} else {
		header('Content-Disposition: attachment; filename="'.$item.'"');
		header('Cache-Control: no-cache, must-revalidate');
		header('Pragma: no-cache');
	}
	
	@readfile($abs_item);
	exit;
}

switch(strtolower($endigung)){
	case '.pps':
		$contenttypedatei='application/vnd.ms-powerpoint';
		break;
	case '.doc':
		$contenttypedatei='application/msword';
		break;
	case '.xls':
		$contenttypedatei='application/vnd.ms-excel';
		break;
	case '.jpeg':
		$contenttypedatei='image/jpeg';
		break;
	case '.jpg':
		$contenttypedatei='image/jpeg';
		break;
	case '.jpe':
		$contenttypedatei='image/jpeg';
		break;
	case '.mpeg':
		$contenttypedatei='video/mpeg';
		break;
	case '.mpg':
		$contenttypedatei='video/mpeg';
		break;
	case '.mpe':
		$contenttypedatei='video/mpeg';
		break;
	case '.mov':
		$contenttypedatei='video/quicktime';
		break;
	case '.avi':
		$contenttypedatei='video/x-msvideo';
		break;
	case '.pdf':
		$contenttypedatei='application/pdf';
		break;
	case '.svg':
		$contenttypedatei='image/svg+xml';
		break;
	case '.flv':
		$contenttypedatei='video/x-flv';
		break;
	case '.swf':
		$contenttypedatei='application/x-shockwave-flash';
		break;
	default:
		$contenttypedatei='application/octet-stream';
		break;
}

header("Pragma: private");
header("Expires: 0"); // set expiration time
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header('Content-Type: '.$contenttypedatei);
if ($forcedownload == true){
	header('Content-Disposition: attachment; filename="'.basename($file).'"');
}else{
	header('Content-Disposition: inline; filename="'.basename($file).'"');
}
readfile($file);

if (file_exists($filePath.$data["filename"])) {
	$ext = substr($data["filename"],-3);
	switch($ext){
	   case "pdf": $ctype="application/pdf";                break;
	   case "exe": $ctype="application/octet-stream";        break;
	   case "zip": $ctype="application/zip";                break;
	   case "doc": $ctype="application/msword";                break;
	   case "xls": $ctype="application/vnd.ms-excel";        break;
	   case "ppt": $ctype="application/vnd.ms-powerpoint";    break;
	   case "gif": $ctype="image/gif";                        break;
	   case "png": $ctype="image/png";                        break;
	   case "jpg": $ctype="image/jpg";                        break;
	   default:    $ctype="application/force-download";
	}
	header("Pragma: public");
	header("Expires: 0");
	header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
	header("Content-Type: $ctype");
	$user_agent = strtolower ($_SERVER["HTTP_USER_AGENT"]);
	if ((is_integer (strpos($user_agent, "msie"))) && (is_integer (strpos($user_agent, "win")))) {
	   header("Content-Disposition: filename=".basename($data['filename']).";");
	} else {
	   header("Content-Disposition: attachment; filename=".basename($data['filename']).";");
	}
	header("Content-Transfer-Encoding: binary");
	header("Content-Length: ".filesize($filePath.$data['filename']));
	readfile($filePath.$data['filename']);
} else {
	die('ERROR: ...');
}