Image steganography is a mechanism that imperceptibly conceals information in a cover image while also enabling the concealed details to be reliably retrieved from that image. The three important criteria for calculating the effect and impact of any steganographic method are high embedding ability, better visual quality and privacy and security. In this paper, a double layered pencil shaped shell matrix based image steganography methodology with high security is proposed and with this extra layer an extra 2 bits can be hidden within every single pixel pair of the pencil shaped shell matrix. Dependent on the shell matrix made of pencil-shaped shells, every private digit is fitted in each cover pixel pair. Various experimental outcomes imply that the proposed methodology has achieved a higher capacity of 3.0 bpp with average 43.25 dB of PSNR and it outperforms other existing shell matrix based image steganographic schemes. Furthermore, the results of RS analysis, JPEG compression analysis, Q-index analysis, normalized absolute error (NAE) analysis etc. are clearly proves the robustness and security of the proposed methodology. Numerous sectors of various private and government organizations, including intellectual property rights, education, intelligent bureau, defence, etc. can be benefited immensely from this scheme.