1. A method for extracting an image from a video, comprising: acquiring a target image corresponding to a target object in a T th frame; acquiring original image resolution S 0 of the T th frame, wherein T is a positive integer; determining a resolution parameter P of the target image; obtaining extraction resolution S 1 according to the original image resolution S 0 and the resolution parameter P; and extracting an image of the target object in a (T+1) th frame according to the extraction resolution S 1 .