Ghostscript is a processor for PostScript and PDF files. It can rasterize these files to a wide variety of printers, devices for screen preview, and image file formats. Since applications tend to prepare pages for printing in a high-level format such as PostScript, most Unix users with low-level bitmap printers, such as inkjets, use GhostScript as part of the printing process. In addition, Ghostscript is capable of converting PostScript files, functionality comparable to Adobe Acrobat Distiller, but on the command line. In addition, Ghostscript is used for file import and viewing by a great many other applications, including xv, ImageMagick, gimp, and xdvi. Several GUI wrappers for viewing PostScript and PDF files exist, including GSview, ghostview, gv, ggv, and kghostview. This is far from a comprehensive list.
album is a free HTML/XHTML photo album and gallery generator that supports themes/skins. You can choose different themes or write your own to get different layouts and styles. It creates all your thumbnails (including directory thumbnails) and descends into directories so you can organize your photos. See the home page for more examples. album is also multi-lingual, with many languages being added all the time. N.B.: The purchase link is provided for donations; the software does not cost anything.
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.
DeuTex is a wad composer for Doom, Heretic, Hexen and Strife. It can be used to extract the lumps of a wad and save them as individual files. Conversely, it can also build a wad from separate files. When extracting a lump to a file, it does not just copy the raw data, it converts it to an appropriate format (such as PPM for graphics, .au for samples, etc.). When it reads files for inclusion in pwads, it does the necessary reciprocal conversions. In addition, DeuTex has functions such as merging wads, etc.
The Geospatial Data Abstraction Library (GDAL) is a unifying C/C++ API for accessing raster geospatial data, and currently includes formats like GeoTIFF, Erdas Imagine, Arc/Info Binary, CEOS, DTED, GXF, and SDTS. It is intended to provide efficient access, suitable for use in viewer applications, and also attempts to preserve coordinate systems and metadata. Python, C, and C++ interfaces are available.
hp2xx is a versatile tool to convert vector-oriented graphics data given in Hewlett-Packard's HP-GL (a.k.a. HPGL) plotter language into a variety of popular both vector- and raster-oriented graphics formats. The various supported output formats include Encapsulated PostScript (EPS), PCX, IMG, and several formats intended to facilitate the generation of graphics within TeX documents. In addition, hp2xx output is printable on the HP Laserjet/Deskjet printer series, and it may be used as a HP-GL previewer on many platforms, e.g. X11 and DOS (VGA).
Jhead is a command line driven utility for extracting digital camera settings from the Exif format files used by many digital cameras. It handles the various confusing ways these can be expressed, and displays them as F-stop, shutter speed, etc. It is also able to reduce the size of digital camera JPEGs without loss of information, by deleting integral thumbnails that digital cameras put into the Exif header. If you need to add Exif support to a program, this is a simple program to cut and paste from. Many projects, including PHP, have reused code from this utility.
KVEC is a command line tool that allows you to convert raster graphics to vector graphics. KVEC is designed for 32 bit operating systems and runs on Win32, OS/2, HP-UX, NEXTSTEP, Linux, IRIX, AIX 4.x, Macintosh and BeOS. Docs are available in English and German. The shareware version is available for 30 day trial.
PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.