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.
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.
Fotoxx navigates an image collection using a thumbnail browser to choose images to view or edit. Edit functions include brightness, contrast, color, gamma, white balance, tone mapping, red eyes, sharpen, blur, noise suppression, smart erase, trim (crop), resize, rotate, add text, bend/warp, many art effects, HDR, HDF, stack, and panorama. Edit functions use movable curves and sliders. Feedback is live using the whole image. RAW files can be edited and saved with deep color. Areas or objects can be selected using freehand draw, follow edge, and tone matching. Selections can be edited in place with adjustable blending. They can also be cut and pasted into other images. Any metadata can be edited, reported, and searched (filenames, tags, dates, geotags, comments, captions, ratings, etc.). Collections (arbitrary subsets) can be defined and viewed. Batch functions are available for rename, resize/export, RAW conversion, and more.
Dia is a program for creating diagrams of all kinds. The current version can do UML class diagrams, Entity-Relationship modeling, network diagrams, and much more. The engine is very flexible and dynamically loads diagram-types from disk. It stores diagrams in an XML format, but can read and write a number of different formats.
GRASS (the Geographic Resources Analysis Support System) is a software raster- and vector-based GIS (Geographic Information System), image processing system, graphics production system, and spatial modeling system. It contains many modules for raster data manipulation, vector data manipulation, rendering images on the monitor or paper, multispectral image geocoding and processing, point data management and general data management. It also has tools for interfacing with digitizers, scanners, and the PostgreSQL, DBF, and ODBC connected databases. GRASS operates on all common operating systems.
Inkscape is a drawing tool with capabilities similar to Illustrator, Freehand, and CorelDraw that uses the W3C standard scalable vector graphics format (SVG). The supported SVG features include basic shapes, paths, text, markers, clones, alpha blending, transforms, gradients, and grouping. In addition, it supports Creative Commons meta-data, node-editing, layers, complex path operations, text-on-path, and SVG XML editing. It also imports several formats like EPS, Postscript, JPEG, PNG, BMP, and TIFF and exports PNG as well as multiple vector-based formats.
Audacity is a cross-platform multitrack audio editor. It allows you to record sounds directly or to import Ogg, WAV, AIFF, AU, IRCAM, or MP3 files. It features a few simple effects, all of the editing features you should need, and unlimited undo. The audio I/O uses PortAudio, which fully supports OSS, Mac OS X CoreAudio, and Windows WMME, and can be compiled with support for ALSA and Jack.