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.
ansi2gif lets you re-live your old BBS ANSI creating days. Any files with text and ANSI-compliant escape codes can be turned into a GIF, PNG, or EPS. This includes animations and files with blinking attributes which are turned into animated GIFs. You can time the speed of the animation.
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.
Gifsicle is a powerful command-line program for manipulating GIF image files. It has good support for transparency and colormap manipulation, simple image transformations (cropping, flipping), and creating, deconstructing, and editing GIF animations. It can also optimize GIF animations for space. Also included is a GIF animation viewer and a program that checks whether two GIFs look the same.
ICCLIB implements support for reading and writing of color profile files that conform to the International Color Consortium (ICC) Profile Format Specification, Version 3.4. The ICC Profile Format is a cross-platform device profile format that can be used to translate color data created on one device into another device's native color space. See the profile specification at color.org. In summary ICCLIB provides support for all version 3.4 header elements, Tags, and Tag Types, conversion to/from machine native representation of all data types, user-defined Tags, adding/deleting Tags, Tag type sharing within a file (often used for sharing LUTs amongst intents), reading/writing embedded profiles, a single function for transforming color values through a profile (including support for intents, forward and reverse transforms, gamut lookup or preview lookup), support and code examples for creating all profile types, monochrome, matrix, and Lut, and it loads Tag Types on demand to conserve memory space.
icontact is a highly-configurable Perl script that takes a bunch of image files and creates contact sheets. icontact determines the file format by the file name extension of the input files, and then uses internal tables to look up the commands it needs to execute in order to convert the images to the PPM format. Once they're converted, icontact uses various pbmplus commands to create contact sheets. icontact is particularly useful if you have lots of image files in all sorts of different formats and you want to create an index of all of them without converting them all to a common format first. This package also includes a filter to convert xv's .xvpics files into PPM format.