Functions.php

function my_admin_scripts() {
wp_enqueue_script('media-upload');
wp_enqueue_script('thickbox');
wp_register_script('my-upload', get_template_directory_uri().'/library/imageupload.js', array('jquery','media-upload','thickbox'));
wp_enqueue_script('my-upload');
}

function my_admin_styles() {
wp_enqueue_style('thickbox');
}

add_action('admin_print_scripts', 'my_admin_scripts');
add_action('admin_print_styles', 'my_admin_styles');