Nowadays image encryption methods are mostly confined to a square image encryption

it proposed a new encryption algorithm which can be applied to both square and rectangular image encryption. Apply the new map that based on image segmentation to the location scrambling

and carry out image gray scrambling by using spread function that contain chaos map

so as to get an image encryption algorithm which combine position and gray scrambling. The results of Simulation show that this algorithm can achieve good image encryption of any size

and has a large key space

key sensitivity and it also has many other advantages such as withstand statistical and known expressly attack.