Graphics and Photo:

Wings 3D is a free and open source polygon mesh subdivision modeller ideally suited for modeling and texturing low to medium density polygon meshes. It has a wide range of very effective tools optimised for these tasks hidden behind its ‘minimalistic’ interface.

Axel is an algebraic geometric modeler which aims to provide “algebraic modeling” tools for the manipulation and computation with implicit and parametric curves or surfaces.

The Persistence of Vision Raytracer, or POV-Ray, is a cross platform ray tracing program for creating stunning three-dimensional graphics.

OGRE (Object-Oriented Graphics Rendering Engine) is a scene-oriented, flexible 3D engine written in C++ designed to make it easier and more intuitive for developers to produce applications utilising hardware-accelerated 3D graphics.

OpenFX is an Open-Source 3D modeling, animation and rendering suite created by Dr. Stuart Ferguson. Its powerful feature-set includes a full renderer and raytrace engine, NURBS support, kinematics-based animation, morphing, and an extensive plugin API.

Art of Illusion is a 3D modelling and rendering studio. It is written entirely in Java, and should be usable on any Java Virtual Machine.

Crystal Space is a free cross-platform software development kit for realtime 3D graphics and in particular games. Officially supports Linux, OSX and Windows.

Blender is a respected 3D content creation suite, available for all major operating systems and distributed under GPL licensing. Create models, shade, animate and make interactive 3D.

imgSeek is a photo collection manager and viewer with content-based search and many other features. The query is expressed either as a rough sketch painted by the user or as another image you supply (or an image in your collection).

MTPaint is a light-weight graphics editor and paint program for Windows and Linux that comes with an interesting feature set.

The PosteRazor cuts a raster image into pieces which can afterwards be printed out and assembled to a poster.

Seashore is an open source image editor for Mac OS X’s Cocoa framework. It features gradients, textures and anti-aliasing for both text and brush strokes.

Xara Xtreme for Linux is a powerful, general purpose graphics program for Unix platforms including Linux, FreeBSD and (in development) OS-X.

Hugin is an easy to use cross-platform panoramic imaging tool. You can assemble a mosaic of photographs into an immersive panorama image, stitch any series of overlapping pictures and much more.

Paint.NET is free image and photo editing software for Windows operating systems. It’s many features include features an intuitive user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools.

GIMP is the definitive GNU image manipulation software, ideal for tasks such as photo retouching, image composition and image authoring. It works across most operating systems and is delivered in a variety of different languages.

ZScreen is an open-source screen capture program that allows for region, window, and full-screen screenshots. It can FTP screenshots and put the URL in your clipboard in a single keystroke.

Inskscape is a great vector graphics editor, with capabilities similar to Illustrator, CorelDraw, or Xara X, using the W3C standard Scalable Vector Graphics (SVG) file format.