use Sirius\Upload\Handler as UploadHandler;
$uploadHandler = new UploadHandler('/path/to/local_folder');

// validation rules
$uploadHandler->addRule('extension', ['allowed' => ['jpg', 'jpeg', 'png']], '{label} should be a valid image (jpg, jpeg, png)', 'Profile picture');
$uploadHandler->addRule('size', ['max' => '20M'], '{label} should have less than {max}', 'Profile picture');

$result = $uploadHandler->process($_FILES['picture']); // ex: subdirectory/my_headshot.png

if ($result->isValid()) {
	// do something with the image like attaching it to a model etc
	try {
		$profile->picture = $result->name;
		$profile->save();
		$result->confirm(); // this will remove the .lock file
	} catch (\Exception $e) {
		// something wrong happened, we don't need the uploaded files anymore
		$result->clear();
		throw $e;
	}
} else {
	// image was not moved to the container, where are error messages
	$messages = $result->getMessages();
}