Wordpress Metabox with uploader

functions.php

<?php

// Add metabox
function dfw_slideshow_metabox() {
    add_meta_box(
        'dfw-metabox',
        'Slideshow',
        'dfw_slideshow_metabox_content',
        'post',
        'side'
    );
}
add_action('admin_init', 'dfw_slideshow_metabox');

// Add contant for metabox
function dfw_slideshow_metabox_content() {
    global $post;
    wp_nonce_field(__FILE__, 'slideshow_metabox_nonce');
?>

<div id="dfw-ahhc-side-wrap">
    <p><label for="dfw_slideshow" style="margin-right:5px;"><?php _e('Exibir post no slideshow:', 'dfwtheme'); ?></label>
    <input type="checkbox" id="dfw_slideshow" name="dfw_slideshow" value="1" <?php checked(get_post_meta($post->ID, 'dfw_slideshow', true), 1); ?> /></p>
    <?php $slide_thumb = get_post_meta($post->ID, 'dfw_slideshow_thumb', true); ?>
    <p><label for="dfw_slideshow_thumb"><?php _e('Imagem:', 'dfwtheme'); ?></label><br />
        <input id="dfw_slideshow_thumb" type="text" name="dfw_slideshow_thumb" style="width:50%;" value="<?php if (!empty($slide_thumb)) echo $slide_thumb; ?>" />
        <input id="dfw_slideshow_thumb_button" type="button" class="button" value="<?php _e('Fazer upload', 'dfwtheme') ?>" />
    </p>
    <script type="text/javascript">
        jQuery(document).ready(function($) {
            var formfield;
            var header_clicked = false;
            $('#dfw_slideshow_thumb_button').click(function() {
                formfield = $('#dfw_slideshow_thumb').attr('name');
                tb_show('', 'media-upload.php?post_id=<?php echo $post->ID; ?>&TB_iframe=true');
                header_clicked = true;
                return false;
            });
            window.original_send_to_editor = window.send_to_editor;
            window.send_to_editor = function(html) {
                if (header_clicked) {
                    fileurl = $(html).attr('href');
                    $('#dfw_slideshow_thumb').val(fileurl);
                    header_clicked = false;
                    tb_remove();
                } else {
                    window.original_send_to_editor(html);
                }
            }
        });
  </script>
</div>
    <?php
}

// Save metabox
function dfw_slideshow_save_metabox($post_id) {

    if (isset($_POST['slideshow_metabox_nonce']) && !wp_verify_nonce($_POST['slideshow_metabox_nonce'], __FILE__))
        return;

    if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE)
        return $post_id;

    if (!current_user_can('edit_post', $post_id))
        return $post_id;

    if (get_post_type($post_id) == 'post' && $_POST) {
        // Save checkbox
        $value_new = esc_attr($_POST['dfw_slideshow']);
        update_post_meta($post_id, 'dfw_slideshow', $value_new);
        // Save image
        $value_img = esc_attr($_POST['dfw_slideshow_thumb']);
        update_post_meta($post_id, 'dfw_slideshow_thumb', $value_img);
    }

    return $post_id;
}
add_action('save_post', 'dfw_slideshow_save_metabox');