1. A method for storing an image sequence, comprising: forming a pixel-bit sequence, each pixel bit corresponding to a position and order of each pixel in each of image frames of the image sequence; comparing a preceding pixel value representing a pixel value of each pixel-bit position of a preceding image frame with a succeeding pixel value representing a pixel value of a corresponding pixel-bit position of a succeeding image frame; and recording a number of times of a preceding pixel value that occurs in consecutive image frames in the image sequence, wherein the comparing and the recording comprise (a) if an absolute value of a difference between a preceding pixel value and a succeeding pixel value is less than a predetermined threshold, treating the preceding pixel value equal to the succeeding pixel value, recording the preceding pixel value in place of the succeeding pixel value, and storing the number of times of the preceding pixel value in a corresponding pixel-bit position in the image sequence, wherein when there is a subsequent image frame to be processed within the image sequence, the preceding pixel value remains as a preceding pixel value to be used iteratively compare with a new succeeding pixel value corresponding to the same pixel-bit position of a subsequent image frame adjacent to the succeeding image frame; (b) if the absolute value of the difference between the preceding pixel value and the succeeding pixel value is greater than the predetermined threshold, recording and/or storing the preceding pixel value, and storing the number of times of consecutively repeated presence of the preceding pixel value in the corresponding pixel-bit position in the image sequence; (c) otherwise recording the remaining succeeding pixel value and storing the number of times of consecutively repeated presence of the succeeding pixel value in the pixel-bit position in the image sequence, wherein when there is a subsequent image frame to be processed within the image sequence, the succeeding pixel value is set as a new preceding pixel value to be used to iteratively compare with a new succeeding pixel value that is a pixel value of the same pixel-bit position of a subsequent image frame adjacent to the succeeding image frame.