# Img Manual

Introduction | Installation | Format handlers | External libraries

### External libraries

Included in this distribution are the most recent versions (as of july 2006) of the libz, libpng, libjpeg and libtiff libraries. These are not required for compilation of libimg, unless you need support for the PNG, JPEG or TIFF formats. If your system already has shared libraries for these formats, probably it will already work with this package. Otherwise the tools are here to build it any time later.

If your system already has later versions than the ones distributed together with Img, it is recommended that you always use the latest available version. In the case of JPEG no promise is made that future versions of the JPEG library keep binary compatiblility, so it might be that you need to recompile Img using the latest JPEG header files. If you don't want the trouble of recompiling Img, it's problably best to stick with libjpeg 6b.

If you want more information about the external libraries, all of them have the latest information readily available on the internet. Img uses unmodified versions of those libraries, except that it provides its own set of makefiles. The reason for this is that not all libraries supply very good support for building them as a shared library. But if you already have them available as a shared library, there should be no need to rebuild them. Here is an overview.

zlib
  http://www.zlib.net/
libpng
  http://www.libpng.org/pub/png/libpng.html
libtiff
  http://www.libtiff.org/
libjpeg
  http://www.ijg.org/files/jpegsrc.v6b.tar.gz
ghostscript (needed for Postscipt reading)
  http://www.cs.wisc.edu/~ghost/

If you have a problems with any of those libraries, please first try to recompile them using the makefiles supplied by Img. If that works, it's an indication that something is wrong with the original distribution of the libraries, and you better report it to the instance where you got it.