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.
Image Viewer is a multi-frame (animated) image viewer with real-time interactive pan and zoom viewing that uses the GTK+ toolkit and Imlib. It is capable of opening and saving to any image format supported by Imlib. It features screenshots (screen capture), crop, resizing, print, fullscreen display, display on the desktop (root window), animation (creating animated GIFs), color leveling, drawing font/text strings, and editing image header information.
makethumbs is a Bourne shell script which creates static HTML image galleries suitable for web or CDROM presentations. It is designed for portability and depends on the fewest possible helper programs. You can simply run makethumbs in a directory of JPEGs and get a usable set of web pages. If you have the time, you can add captions, descriptions, and create a dotrc file to completely change the look and feel of the generated gallery. A small helper script, rotate.sh, is also available to easily fix rotated images.
tif22pnm is a command line utility that converts between TIFF sampled images and PNM images (both directions), using the libtiff library, but not using NetPBM. tif22pnm is similar to the tifftopnm utility in the NetPBM distribution, but tif22pnm handles a wider range of TIFF files and is able to output the alpha channel as a PBM or PGM file. png22pnm, a converter from PNG to PNM, is also bundled into the distribution.
sam2p is a Unix commandline utility that converts many raster (bitmap) image formats into Adobe PostScript or PDF files. The images are not vectorized. It gives full control to the user to specify standards-compliance, compression, and bit depths. It is common that sam2p can compress an image down to an 50kB Level1 PostScript file without quality loss, while other popular converters produce multi-megabyte output. It provides some Level3 compression filters even on Level1 devices.
"Jpegpixi" is short for "JPEG pixel interpolator". It is a command-line utility which interpolates pixels in JFIF images (commonly refered to as "JPEG images"). This is useful to correct images from a digital camera with CCD defects. Jpegpixi is unique in that it tries to preserve the quality of the JFIF image as much as possible. Most graphics programs decode JFIF images when they are loaded, and re-encode them when they are saved, which results in an overall loss of quality. Jpegpixi, on the other hand, does not decode and re-encode the image, but manipulates the encoded image data, protecting the quality of the image as much as possible.
Jpgtn generates smaller JPEGs from larger ones. It can work in batches and create new files with names based on the names of the source files. It can dump a single thumbnail to stdout for use with pipelines or CGI programs. Thumbnail size and quality can be controlled by switches on the command line. There is no maximum "thumbnail" size, so it can be useful for creating images suitable for web publishing from very large images such as those taken with a good digicam.