In this paper, a novel image encryption scheme is proposed based on combination of pixel shuffling and W7. Due to sensitivity to initial conditions, chaotic maps have a good potential for designing dynamic permutation map. So a chaotic Henon map is used to generate permutation matrix. An external secret key is used to derive the initial conditions for the chaotic map and W7 secret key. Pixel shuffling is performed via vertical and horizontal permutation. Shuffling is used to expand diffusion in the image and dissipate the high correlation among image pixels. In order to evaluate performance, the proposed algorithm was measured through a series of tests. Experimental results illustrate that the scheme is highly key sensitive and shows a good resistance against brute-force and statistical attacks.