In this paper a new two-dimensional map is proposed. It is a process of stretch-and-fold. Firstly a square image is divide two parts according diagonal. Secondly each part of image is stretch respectively and joins a line. Lastly the line is fold over to a new square image of same size. The map divides into the left map and the right map. The process shuffles the positions of image pixels. Comparing the prevalent twodimensional map, Cat map and Baker map, the new map has simple formulation, big keys space which is fit for image encryption. An image encryption scheme based on the map is developed. The numbers of the left map and the right map are used as the key. The deciphering process is opposite using the same keys. The results of simulation show that it can be used in real-time image encryption applications.