Uploading images/files in TinyMCE

<script src='http://kurapa.com/js/tinymce/tinymce.min.js' type='text/javascript'></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
tinymce.init({
	selector: 'textarea',
	content_style: 'body { font-size: 10pt; font-family: 맑은 고딕체,Calibri,Arial,Sans-serif; }',
	themes: 'modern',
	plugins: "image media",
	file_picker_callback: function(callback, value, meta)
	{
		// File type
		if (meta.filetype =="media" || meta.filetype =="image")
		{
			// Trigger click on file element
			jQuery("#fileupload").trigger("click");
			$("#fileupload").unbind('change');

			// File selection
			jQuery("#fileupload").on("change", function()
				{
					var file = this.files[0];
					var reader = new FileReader();

					// FormData
					var fd = new FormData();
					var files = file;
					fd.append("file",files);
					fd.append('filetype',meta.filetype);

					var filename = "";

					// AJAX
					jQuery.ajax({
						url: "upload.php",
						type: "post",
						data: fd,
						contentType: false,
						processData: false,
						async: false,
						success: function(response)
						{
							filename = response;
						}
					});

					reader.onload = function(e)
					{
						callback("upload/"+filename);
					};

					reader.readAsDataURL(file);
				}
			);
		}

	}

});
</script>

<form method=post action="output.php">
	Title<br>
	<input type=hidden name="cid" value="<?=$cid?>">
	<input type=text name="title" value="" size=80><br>
	<textarea cols=80 rows=40 name="body"></textarea>
	<input type='file' name='fileupload' id='fileupload' style='display: none;'>
	<input type=submit>
</form>

<?php

// Getting file name
$filename = $_FILES['file']['name'];

// file type
$filetype = $_POST['filetype'];

// Valid extension
if($filetype == 'image'){
  $valid_ext = array('png','jpeg','jpg');
}else if($filetype == 'media'){
  $valid_ext = array('mp4','mp3');
}

// Location
$location = "upload/".$filename;

// file extension
$file_extension = pathinfo($location, PATHINFO_EXTENSION);
$file_extension = strtolower($file_extension);

$return_filename = "";

// Check extension
if(in_array($file_extension,$valid_ext)){

  // Upload file
  if(move_uploaded_file($_FILES['file']['tmp_name'],$location)){

    $return_filename = $filename;

  }

}

echo $return_filename;

?>