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.
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.
JLM image viewer is able to view standard image types as well as JLM and PLM image types. It is also able to lighten or darken an image using a "lightspace" technique. The technique is equivalent to changing the exposure time of the camera which took the image. The lightening or darkening method is generally considered superior to techniques found (such as gamma correction) which are found in image manipulation programs such as photoshop or the GIMP.
Kabeja is a Java library for parsing CAD data (i.e. Autodesk's DXF format) and converting to SVG (dxf2svg). You can use Kabeja from the command line or embed it into your application. It includes a plain DXF2SVGViewer and integration into the Cocoon XML Web development framework and the Inkscape SVG editor.
LinPHA is an easy-to-use, multilingual, flexible photo/image archive/album/gallery written in PHP. It uses an SQL database (MySQL/PostgreSQL/SQLite) to store information about your pictures. It comes with an HTML-based installer, so you don't need experience in setting up SQL databases. Thumbnails are created as needed and stored in the SQL DB. It features complete user management, top ten statistics, hidden albums, different themes, slideshow, filemanager, uploader, watermarks, benchmark, printing, and more.
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.