[Correct Way To Com,press JPG With GD Library]

I know what jpeg compression is, what's your point?

[Correct Way To Com,press JPG With GD Library]

Hello, what's the correct use of GD library to compress JPG images please? I am using this upload script with TinyMCE. See below :

I have this snippet but it doesn't compress the image:

		// Accept upload if there was no origin, or if it is an accepted origin
		// If image is JPEG compress with GD library
		$filetowrite = $imageFolder . $temp['name'];
		if (in_array(strtolower(pathinfo($temp['name'], PATHINFO_EXTENSION)), array("jpg", "jpeg"))) {
		imagejpeg($temp['tmp_name'], $filetowrite, 75);
		} else {
		move_uploaded_file($temp['tmp_name'], $filetowrite);
		}

<?php
	$accepted_origins = array("http://localhost", "http://127.0.0.1", "http://192.168.1.1", "http://example.com");

	$month = strtolower(date('M'));
	$year = date('Y');
	$newspath = "img/news/";

	if (!is_dir("$newspath/$year/$month")) {
    mkdir("$newspath/$year/$month", 0777, true);
}
	$imageFolder = "$newspath/$year/$month/";

	reset ($_FILES);
	$temp = current($_FILES);
	if (is_uploaded_file($temp['tmp_name'])){
		if (isset($_SERVER['HTTP_ORIGIN'])) {
			// same-origin requests won't set an origin. If the origin is set, it must be valid.
			if (in_array($_SERVER['HTTP_ORIGIN'], $accepted_origins)) {
				header('Access-Control-Allow-Origin: ' . $_SERVER['HTTP_ORIGIN']);
			} else {
				header("HTTP/1.1 403 Origin Denied");
				return;
			}
		}

		/*
			If your script needs to receive cookies, set images_upload_credentials : true in
			the configuration and enable the following two headers.
		*/
		// header('Access-Control-Allow-Credentials: true');
		// header('P3P: CP="There is no P3P policy."');

		// Sanitize input
		if (preg_match("/([^\w\s\d\-_~,;:\[\]\(\).])|([\.]{2,})/", $temp['name'])) {
				header("HTTP/1.1 400 Invalid file name.");
				return;
		}

		// Verify extension
		if (!in_array(strtolower(pathinfo($temp['name'], PATHINFO_EXTENSION)), array("gif", "jpg", "jpeg", "png"))) {
				header("HTTP/1.1 400 Invalid extension.");
				return;
		}

		// Accept upload if there was no origin, or if it is an accepted origin
		// If image is JPEG compress with GD library
		$filetowrite = $imageFolder . $temp['name'];
		if (in_array(strtolower(pathinfo($temp['name'], PATHINFO_EXTENSION)), array("jpg", "jpeg"))) {
		imagejpeg($temp['tmp_name'], $filetowrite, 75);
		} else {
		move_uploaded_file($temp['tmp_name'], $filetowrite);
		}
		// Respond to the successful upload with JSON.
		// Use a location key to specify the path to the saved image resource.
		// { location : '/your/uploaded/image/file'}
		// echo json_encode(array('location' => $filetowrite));

		$passpath = $year.'/'.$month.'/'.$temp['name'];

		echo json_encode(array('location' => $passpath));
	} else {
		// Notify editor that the upload failed
		header("HTTP/1.1 500 Server Error");
	}
?>