<p>Digilib is a web based client/server technology for images. The image content is processed on-the-fly by a Java Servlet on the server side so that only the visible portion of the image is sent to the web browser on the client side. It supports a wide range of image formats and viewing options on the server side while only requiring an internet browser with javascript and a low bandwidth internet connection on the client side. digilib enables very detailed work on an image as required by scientists with elaborate zoom features like an option to show images on the screen in their original size. digilib facilitates cooperation of scientists over the internet and novel uses of source material by image annotations and stable references that can be embedded in URLs. digilib is used in the ALCATRAZ framework of image, text and annotation tools and many other projects.</p>