GAIA Image Transcoder (GIT) is a library that operates image transcoding, with a special focus on mobile applications. It comes in two parts: a transformation and transcoding library that performs image adaptation to mobile device using information retrieved from WURFL files, and a very simple JSP tag library that enables library utilization in a J2EE environment. The transcoding library works as a transformation pipeline. The pipeline is composed of a set of filters. A filter can operate directly on the image body, or indirectly on the associated meta-information. The GIT architecture supports the management cycle of such pipes, while GIT tag libraries simplifies their definition.