The Gallery Wizard can be used to create image galleries from a given directory of images. It allows you to specify how many images per row, and how many rows to have per page. If the number of images in the directory is greater than the number of rows * the number of columns then another page will be created, and links between the two pages will be inserted.
All the images will have thumbnails created which will be links to the full size image. Currently the resulting HTML files will be in the same directory as the images. This plugin can be used without having a site or page open.