...Features: FTP Browser, Exif viewer, Thumbnail and Image processing, HTML generation, CSS styles, slideshow (Javascript or JavaFX). Just build your gallery and upload. You won't need Ruby on the server.
GImageView is a GTK+ based image viewer which supports tabbed browsing, thumbnail table views, directory tree views and drag and drop. It also support movies using the Xine library and MPlayer, and supports images in compressed archive formats.