This paper proposes a new image encryption technique based on a new chaotic system consists of joining two chaotic maps: the logistic chaotic map and the cubic chaotic map. This chaotic system is used to encrypt the R, G, B components of a colored image at the same time and the three components affect each other. So the correlations between R, G, and B components were reduced and the security of algorithm was increased. Simulation results show that the algorithm satisfy the required performance tests such as high level security and large key space which larger than the key space of related work.