Media discovery and content storage within and across devices

In various example embodiments, a system and method for visual search and associated data decay models are presented. In one example embodiment, image history data associated with an output display of the machine is captured. The image history data is analyzed to identify groups of images associated with a plurality of events, and context information is identified that is associated with the plurality of events. One or more images for each event of the plurality of events is selected as a key image for an associated event as part of a plurality of key images, and a searchable event timeline index is generated. Key frames from an index of activities of one or more devices may then be displayed as part of a user search for information.