WordPress/wp-admin/media-upload.php

<?php
/**
 * Manage media uploaded file.
 *
 * There are many filters in here for media. Plugins can extend functionality
 * by hooking into the filters.
 *
 * @package WordPress
 * @subpackage Administration
 */

/** Load WordPress Administration Bootstrap */
require_once('admin.php');
wp_enqueue_script('swfupload');
wp_enqueue_script('swfupload-degrade');
wp_enqueue_script('swfupload-queue');
wp_enqueue_script('swfupload-handlers');

@header('Content-Type: ' . get_option('html_type') . '; charset=' . get_option('blog_charset'));

if (!current_user_can('upload_files'))
	wp_die(__('You do not have permission to upload files.'));

// IDs should be integers
$ID = isset($ID) ? (int) $ID : 0;
$post_id = isset($post_id)? (int) $post_id : 0;

// Require an ID for the edit screen
if ( isset($action) && $action == 'edit' && !$ID )
	wp_die(__("You are not allowed to be here"));

// upload type: image, video, file, ..?
if ( isset($_GET['type']) )
	$type = strval($_GET['type']);
else
	$type = apply_filters('media_upload_default_type', 'file');

// tab: gallery, library, or type-specific
if ( isset($_GET['tab']) )
	$tab = strval($_GET['tab']);
else
	$tab = apply_filters('media_upload_default_tab', 'type');

$body_id = 'media-upload';

// let the action code decide how to handle the request
if ( $tab == 'type' )
	do_action("media_upload_$type");
else
	do_action("media_upload_$tab");

?>