1. A method comprising: by a computing device, accessing a media file associated with a first user; by the computing device, determining a candidate set of one or more second users based on attributes of an event, the attributes comprising a list identifying individuals, wherein the individuals were invited to the event or are registered as attending the event; by the computing device, determining based on a facial-recognition algorithm a matching score of each of one or more of the second users in the candidate set to each of one or more faces in the media file; by the computing device, for each second user with a matching score above a threshold value to a face in the media file: comparing first spatio-temporal information of the media file with second spatio-temporal information of the second user; and adjusting the matching score of the second user to the face based on the comparison; by the computing device, determining one or more potential matches between the second users in the candidate set and the faces in the media file based on the matching scores as adjusted; and by the computing device, tagging the media file with information identifying the event based on one or more of the potential matches between the second users in the candidate set and the faces in the media file.