gThumb is an open-source image viewer and organizer for the GNOME desktop environment released under the GNU General Public License. It was originally based on GQView, and is designed to have a clean, simple interface. The first public version was 0.2 in 2001.
gThumb allows the filesystem to be browsed for images. They can be organized into catalogs, or viewed as a slideshow. Folders and catalogs can be bookmarked, and comments may be added to images.
Via gPhoto it can also acquire data directly from digital cameras.
Many basic image editing features are included, such as: arbitrary rotation, resizing, cropping, and image enhancing filters such as color, brightness and contrast adjustment.
gThumb can export web-based albums with various theme templates. These albums can be uploaded to a website, providing a very simple mechanism for publishing collections of photos on the web.
gThumb also includes many basic features essential to any image viewer such as copying, moving, deleting or duplicating images, printing, zooming, format conversion, and batch renaming.
Starting from version 2.12.0 gThumb allows you to export photos to various websites.
Version 3.0.0 supports GTK3, high quality SVG zoom and includes various bug fixes.