This Thesis, which was written at the University of Technology at Graz and San Diego State University, describes the development of an interactive communication system that allows collaborative work with images over the Internet. The developed system with the name Distributed Graphics Laboratory (DGL) is a synchronous communication tool in the area of Computer-Supported Collaborative Work (CSCW). It allows a group of remotely located users the simultaneous reviewing and processing of images. The system offers various image processing and drawing functions, as well as communication aids in form of annotations and group discussions. The displayed images are synchronized, which means that every user can instantly see changes in images and user actions performed by other users. The analysis of similar, already existing applications showed the importance of platform independence. Hence, the DGL was completely developed in Java. The system's core is a Client/Server Architecture, which uses Java RMI for network communication. Tests showed that the resulting product is very usable, although improvements to increase awareness of remote colleagues should be made in future versions.