Libraries handle ever more digital images. Ancient documents, books, manuscripts are digitized, image processing tools extract and assign keywords to the obtained images, but a manual annotation is almost always essential. Manual image annotation and keyword based image search is a difficult and hardly formalizable problem. In this paper we present a model and a system which addresses this issue. It is an online image annotation and management system, which traces the actions of the users and uses the capitalized experience to help them according to the case based reasoning paradigm. The system provides basic online image gallery features: uploading single or zipped images, describing images with keywords, importing xml based image descriptors, managing galleries … In addition the system helps image annotation tracing the actions of the user in order to propose additional keywords and images as well in the description as in the search phase. This help is provided by the capitalization and the reuse of users’ experience based on the case based reasoning paradigm. After a short introduction we describe our use trace model, the assistance strategies and present the developed prototype.