I have been using the NextGen Gallery plugin for WordPress to handle image galleries. The admin interface is easy to use, even for my clients. Unfortunately the plugin outputs the images into Flash movie, which I wasn’t happy with- so I’ve written code to output the images into a Javascript scroller, which is far more customisable. I can change the next/previous image buttons to suit the style of the website, and I can add a number or thumbnail for each image if I wish.