Netpbm is a toolkit for manipulation of graphic images, including conversion of images between a variety of different formats
From the official project site at sourceforge:
Netpbm consists of over 300 separate tools including converters for about 100 graphics formats. The package is intended to be portable to many platforms. It has, at least at one time, been tested under various Unix-based systems, Windows, Mac OS X, VMS and Amiga OS. The maintainer uses and builds it on a platform that consists (in relevant part) mainly of GNU software (you probably know this kind of system by the name "Linux").
The goal of Netpbm is to be a single source for all the primitive graphics utilities, especially converters, one might need. So if you know of some freely redistributable software in this vein which is not in the package yet, you should bring it to the attention of the Netpbm maintainer so it can be included in the next release.
Netpbm does not contain interactive tools and doesn't have a graphical interface.
