-This paper presents a new approach for hiding the secret image inside another image file, depending on the signature of coefficients. The proposed system consists of two general stages. The first one is the hiding stage which consist of the following steps (Read the cover image and message image, Block collections using the chain code and similarity measure, Apply DCT Transform, Signature of coefficients, Hiding algorithm , Save information of block in boundary, Reconstruct block to stego image and checking process). The second stage is extraction stage which consist of the following steps ( read the stego image, Extract information of block from boundary, Block collection, Apply DCT transform, Extract bits of message and save it to buffer, Extracting message).