A method implemented in a video monitoring system comprising a video camera, a server one or more portable electronic device such as a smartphone or tablet, the method comprising: a—capturing images and determine content change, b—calculate an activity level, with a content change index and a noise index, c—calculate an image storing rate, d—store, at storing rate, time-stamped images, e—transmit time-stamped images to the server, f—build, at the server, a video sequence forming a summary of a predefined past period of time, to be displayed, upon user demand, on the portable electronic device.