I found an interesting article about how to install WordPress on a stick. I haven't tried it, but it looks very useful for portable Web development in general. It uses a portable version of Apache and MySQL called XAMPP.
Gallery is the classic free PHP photo album program for web sites. If you don't have a database on your server you can use Gallery 1. Gallery version 2 requires a database. The Gallery web site has a full list of requirements. Gallery can also be integrated into several content management systems, including Drupal.