Sodipodi is a vector-based drawing program.

Gimp is a powerful image creation and manipulation program.

Blender is a cross plaform 3D creation suite, allowing fully integrated modeling, animation, rendering, post production and interactive 3D creation and playback.

PovRay, the Persistence of Vision Raytracer is a high-quality, open source tool for creating stunning three-dimensional graphics.

Dia is a gtk+ based diagram creation program released under the GPL license

smartision ScreenCopy is a screenshot tool.

Tux Paint" is a drawing program for young children. It provides a simple interface and fixed canvas size, and will provide access to previous images using a thumbnail browser (e.g., no access to the underlying filesystem).

ImageMagick^TM 5.5.7 is a robust collection of tools and libraries offered under a usage license to read, write, and manipulate an image in many image formats (over 87 major formats) including popular formats like TIFF, JPEG, PNG, PDF, PhotoCD, and GIF. With ImageMagick you can create images dynamically, making it suitable for Web applications. You can also resize, rotate, sharpen, color reduce, or add special effects to an image and save your completed work in the same or differing image format. Image processing operations are available from the command line, as well as through C, C++, Perl, or Java programming interfaces.