Pixel is an application for editing, retouching, manipulating, and animating RGB, CMYK, and HDR images. It was formerly known as Pixel32. It is available for Windows, Linux, Linspire, Mac OS X, BeOS, Zeta, QNX, MorphOS, FreeBSD, eComStation, OS/2, SkyOS and even old plain DOS, for both x86 and PowerPC architectures.
view3dscene is a browser for VRML (1.0 and 2.0) and X3D, and a viewer for other 3D model formats (3DS, MD3, Wavefront OBJ, and Collada are handled). It supports viewing the scene in the "Examine" mode and walking in the virtual world with features such as collision detection and gravity. Rendering is done using OpenGL. Many advanced 3D graphic effects are available, like mirrors (flat and through cube environment mapping), shadows (shadow maps and shadow volumes), GLSL shaders and more. The program can also convert files from 3DS, MD3, Collada and other formats to X3D and pretty-print VRML and X3D files.
Mapnik is a toolkit for developing GIS applications. At the core is a C++ shared library providing algorithms/patterns for spatial data access and visualization. Essentially a collection of geographic objects (map, layer, datasource, feature, and geometry), the library doesn't rely on "windowing systems" and can be deployed in any server environment. It is intended to play fair in a multi-threaded environment and is aimed primarily, but not exclusively, at Web-based development. High-level Python bindings (boost.python) facilitate rapid application development, targeting zope3, django, etc.
PECoMaTo stands for Picture-Embedded COntents MAnipulation TOol. It is basically designed to display any kind of information embedded in picture files, as well as checking, filtering, extracting, removing, adding, and fixing such information. In other words, it's a metadata processor. It supports the following file formats: JPEG/JFIF, Adobe PSD and FFO, and raw IPTC. It knows about the following metadata formats: JFIF, IPTC, Exif, Adobe, and Fotostation. More file and metadata formats might be supported later (TIFF, etc.).