The effect called “frozen time” or “bullet time” is achieved, when a moving object is photographed from different angles at the same time from many cameras – a so-called camera array. The resulting pictures are combined together into a film or animation afterwards. If e.g. someone jumps and the pictures are taken in the moment when the person is up “in the air”, the resulting film or animation will move around the jump while time seems to hold on. The more cameras used, the longer the resulting animation or film is. The “frozen time” effect is a very unique combination of both photo and film: On one side the pictures represent a single moment in time as shown on a normal photo, on the other hand they show the characteristics of movement as seen in a film.
See a very fascinating project with some amazing examples at http://www.frozen-time-cam.com.