Colorization is a method which adds color components to grayscale images using color assigned information provided by the user. Recently, a novel approach to image compression called colorization based coding has been proposed. It automatically extracts color assignations from original color images at an encoder and restores color components by colorization method at a decoder. In this paper, we propose the method which improves the conventional color image coding methods by regarding colorization as interpolation. At the encoder, the proposed method subsamples chrominance components considering colorization and subsampled chrominance components are compressed by conventional methods. At the decoder, subsampled chrominance components are interpolated by colorization. Simulations reveal that the proposed method improves quality of reconstructed images, objectively.