GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
Citra FX is a set of image filter effects for digital photos or images. It allows anyone, regardless of experience, to turn digital images into unique artistic looks. Citra FX comes with many prebuilt filters from color adjustment, contrast, and exposure to advanced filters like water ripple, emboss, etc. You also get instant visual feedback on what you changed. It is well suited for both simple and advanced digital photo or image filtering.
Geomajas is an extensible spatial application framework, enabling integrated GIS solutions for businesses and government. It has an integrated client-server architecture, with a high focus on server-side integration of your data (be it through GeoTools or Hibernate). This means that you apply your security and business logic on the server before anything gets sent to the client, resulting in robust applications and a real thin client.
Tux Paint is a simple and entertaining drawing program geared towards young children. It has a simple interface, sound effects, and a cartoon character (Tux, the Linux penguin). Along with drawing brush strokes, lines and shapes, you can also enter text and place "rubber stamp" (or "sticker") images on the picture. Tux Paint is extensible, and could be useful in an educational environment (such as a grammar, elementary, or grade school). It's portable across numerous platforms, and runs well even on slower systems like the Pentium 133MHz.
F-Spot is a personal photo management application for the GNOME desktop. It simplifies digital photography by providing intuitive tools to help you share, touch-up, find, and organize your images. These tools include editing, color adjustments, tags, Photo CD creation, and exporting for upload.
GridFlow is a plugin for PureData, Ruby, and jMax. It provides the ability to process images and video as N-dimensional arrays ("Grids"). It consists of a framework for grid transmissions, elementary grid processing objects, picture-oriented processing objects, and input/output objects. It also allows one to write plugins for PureData and jMax using the Ruby language.
ingimp (Instrumented GIMP) is an instrumented version of the GNU Image Manipulation Program that automatically collects usability (usage) data, such as the commands used, the size of images worked on, and so on. This data is transmitted to ingimp.org where it is analyzed and available for anyone to download. ingimp is intended to shed light onto how the software is actually used in practice. It can be used as a snap-in replacement for the GIMP.