【CakePHP2, jQuery】Ajaxで画像をアップロードする

<?php
    echo $this->Form->create('Image',array('action' => 'add', 'type' => 'file')).PHP_EOL;

    echo $this->Form->input(false,array(
        'type' => 'file',
        'label' => '画像選択',
    )).PHP_EOL;

    echo $this->Form->input('fileName', array(
        'type' => 'text',
        'label' => '画像名',
        'required' => true,
        )).PHP_EOL;

    echo $this->Form->submit('upload',array('id' => 'img')).PHP_EOL;
    echo $this->Form->end().PHP_EOL;
?>

<?php
App::uses('AppController', 'Controller');

class ImagesController extends AppController
{
    public function add()
    {
        if (!empty($this->request->data) && $this->request->is('ajax')) {
            Configure::write('debug',0);
            $this->autoRender = false;
            $this->autoLayout = false;

            $type = array(
                'image/png' => '.png',
                'image/jpeg' => '.jpg',
                'image/gif' => '.gif',
            );

            $fileName = $this->request->data['Image']['fileName']. $type[$this->request->data['Image']['type']];

            move_uploaded_file($this->request->data['Image']['tmp_name'], /ファイルの保存場所/. $fileName);

            $params = array(
                'Image' => array(
                    'name' => $fileName
                )
            );

            if ($this->Image->save($params)) {
                return $fileName;
            } else {
                return 'error';
            }
        }
        exit();
    }
}

$(function()
{
    $("#ImageAddForm").submit(function()
    {
        var fd = new FormData($(this)[0]);

        $.ajax({
            type: 'post',
            url: "/images/add",
            data: fd,
            processData: false,
            contentType: false,
        });

        return false;
    });
});