1. A digital photography method comprising: receiving a definition of a moment at which an anticipated event is to be photographed, said moment comprising a moment at which a moving object arrives at a location; using a digital imaging device residing in a digital camera to generate a stream of digital images of a location at which said event is anticipated to occur; and inspecting said stream of digital images, to anticipate said moment in said stream by predicting the time at which an application-specific change will occur in the scene, and to generate a trigger timed and constructed to trigger generation of an additional image of said location at said moment, said generation of an additional image being effected by an imaging process; said inspecting comprising inspecting said stream of digital images, to anticipate said moment at which imaging should take place, long enough before said moment at which imaging should take place to enable activation of said imaging process, by estimating said moving object's time of arrival at the location using said moving object's current and previous locations and using standard deviation of a difference image histogram between a reference image in said stream and a current image.