lazygal is a free and open source static web gallery generator written in Python.
Here are some key features of "lazygal":
Command line based (thus scriptable).
Reusable engine (to make a GUI for instance).
Lazy : do not build what's already there.
Recursive : generates subgalleries.
Does not change your original pictures directories (the source argument).
Tells you what should not be in your generated directories (and delete it if you want to).
Can generate multiple sizes to browse pictures according to your screen.
Sort pictures in the same directory by EXIF date if available, else file modification time.
XHTML and CSS compliance for provided themes.
Support for per folder meta data.
RSS feed generation for your album updates.
Python 2.4 or later
ElementTree (or Python 2.5 or later)