GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software suitable for such tasks as photo retouching, image composition and image authoring. It can be used as a simple paint program, an expert quality photo retouching program, an online batch processing system, a mass production image renderer, a image format converter, etc.
digiKam is an advanced digital photo management application that makes importing and organizing digital photos a trivial task. Photos can be organized in albums, which can be sorted chronologically, by directory layout, or by custom collections, and they can be tagged, commented, and rated. digiKam makes use of a fast and robust database to store meta-information, which makes adding and editing comments and tags very reliable. Metadata can also be stored inside pictures using Exif and IPTC. An embedded image editor and a standalone application named showfoto have simple but powerful features for editing your pictures with filters and correction tools.
tvpvrd is a PVR daemon for Linux that offers the ability to schedule and manage TV recordings using one or multiple installed analogue TV capture cards, e.g. Hauppauge. The daemon is interfaced either through its full command language via a provided command line shell or through a basic (built-in) Web interface provided by the built in micro Web server. The goal is to provide an advanced recording and transcoding (using ffmpeg) server without the need to configure databases or a complex GUI. The server is completely self-contained and uses an XML DB in plain text format to store future recordings.
Asymptote is a powerful descriptive 2D and 3D vector graphics language for technical drawing, inspired by MetaPost but with an improved C++-like syntax. It provides for figures the same high-quality level of typesetting that LaTeX does for scientific text. Asymptote is a programming language as opposed to just a graphics program. It can exploit the best features of script (command-driven) and graphical user interface (GUI) methods. High-level graphics commands are implemented in the language itself, allowing them to be easily tailored to specific applications.
JGraph is a free, mature, and robust Java diagramming library. It contains all the graph visualization, layout, and interaction functionality you might expect in a graph library, including multiple views, layering, zoom, drag and drop, undo, automatic expanding and collapsing, routing, and layouts. You can create workflow editors, BPMN, CAD tools, network diagrams, database visualization tools, and more. It is fully documented, including examples, and has an active support community.
BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
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.