PhotoMot is an online collaborative image management system which traces the actions of users and provides them assistance based on the capitalized experience according to the case based reasoning paradigm. How to imply the user in the assistance a system provides? PhotoMot shows the trace of user actions being built and lets users interact on the manner they are followed. This way they can help the system provide pertinent assistance. 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. The system provides basic online image gallery features: uploading single or zipped images, describing images with keywords, 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.