File Format Libraries

Zlib (Portable, lossless data compression library based on a "LZ77" compression algorithm variant called "deflation". License: Zlib license) (ml) (technical details) (deflate algorithm)
ZZIPlib (Library for reading ZIP archives based on Zlib. License: LGPL) (ml)

libjpeg (Patent free JPEG image format library implementation for lossy image compression. License: BSD-style)
libtiff (Free TIFF image format library implementation for storing raster-image data. License: BSD-style) (libgeotiff extension of libtiff with a geospatial meta-tag data structure) (cvs) (ml)
libpng (PNG image format read/write library. License: BSD-style) (libmng (The MNG, aka Ming, animated PNG image format)
librsvg (Library for rendering SVG files to other, more conventional types, such as JPEG and PNG. License: LGPL) (cvs) (ml)
JBIG-KIT (Library implementation of the JBIG bi-level image compression standard, optimized for reading and writing of high-resolution, scanned documents. License: GPL)
DjVuLibre (Image encoding and decoding program, including several other tools, for using the lossy image format DjVu.) (patent comments)
libbsb (Library for reading/writing BSB raster image files. This package includes several tools, like: bsb2tif, tif2bsb, ppm2bsb, bsb2ppm. License: LGPL) (cvs)