gPhoto is a program and library framework that lets users download pictures from their digital cameras. The libgphoto2 library gives you access to hundreds of models of digital cameras on several platforms. GIT repo and Issue tracker lives at https://github.com/gphoto/ these days.
GTK+ comic book viewer.
MComix is a user-friendly, customizable image viewer. It is specifically designed to handle comic books (both Western comics and manga) and supports a variety of container formats (including CBR, CBZ, CB7, CBT, LHA and PDF). MComix is a fork of Comix.
GPX viewer and analyzer
GPXSee is a GPS log file viewer and analyzer that supports GPX, TCX, KML, FIT, IGC, NMEA and OziExplorer files.
Comix is a user-friendly, customizable image viewer. It is specifically designed to handle comic books, but also serves as a generic viewer. It reads images in ZIP, RAR or tar archives (also gzip or bzip2 compressed) as well as plain image files.
Simple image comparison tool
DiffImg is a simple image comparison tool which take two images with the same size as input. Some statitics are computed and the positions where pixel differ are displayed as a color mask.
ZoneMinder is video and cctv surveillance and security application. It supports multiple video or IP cameras and a sophisticated motion detection system based around zones. Both live streams and historic events can be viewed via the web interface.
PDFView is a simple, yet powerful, Mac Os X PDF viewer, with advanced integration with LaTeX.
Ultimate Webshots Converter is a Webshots pictures converter. It is able to show and save into JPEG files the pictures contained in the following files : WBC, WBZ, WB1 and WBD.
darknocK detects edges in images. It is using Artificial Neural Networks to enchance the results of standard algorithms.
Geeqie is a lightweight image viewer. It was forked from GQview. The development is focused on features for photo collection maintenance: raw format, Exif/IPTC/XMP metadata and integration with programs like UFraw, ImageMagick, Gimp, gPhoto or ExifTo The current development and project can be found on http://www.geeqie.org/. The sourceforge page will be deleted soon.