libpng 1.6.34 / 1.6.35 Beta 1 Description:
libpng The library is usually installed by default in all modern Linux kernel-based operating systems, if not all distributions, so you will be able to read and write PNG graphics files. Examples and tests are also provided to users in the source package to see if PNG support is fully enabled. Keep in mind though, that libpng is a library, not a command-line program, which means that you won’t be able to interact with it, except for the ‘libpng-config’ command that offers various command-line options. A manpage is provided too, so you learn how to use it in your projects.