AxPoint generates beautiful slideshows in PDF format from a simple XML description format. It is written as a Perl SAX2 handler, but also ships with command line tools. The format supports slide transitions, PDF bookmarks, bullet point transitions, images, text colours, different fonts, and more.
Pictag is a simple web photo gallery with automatic thumbnail generation and tagging capability. It's self-contained in a single file, uses the filesystem for gallery layout, and requires no stand-alone database (it uses SQLite) or no database at all. It handles EXIF data, provides support for HTTP user authentication and authorization, and is customizable.