This paper introduces a practical inter-color up-sampling algorithm for images with decimated chrominance components. Most of the existing and emerging image and video compression coding standards such as JPEG, MPEG and H.26x families employ YCbCr4:2:0 chrominance format. After reconstructing the YCbCr4:2:0 image at a decoder, one must up-sample the decoded chrominance signals by a factor of two in both horizontal and vertical directions to generate the YCbCr4:4:4 format image, which is eventually transformed to RGB color space especially for displaying the reconstructed image. Then, we focus on generating high-fidelity RGB image, (but not an intermediate YCbCr image), and propose an innovative up-sampling algorithm that exploits the RGB inter-channel correlation. This is based on the fact that the RGB inter-channel correlation is usually higher than the YCbCr inter-channel correlation. The simulation results show that the proposed method outperforms the state-of-the-art method and a bi-linear method with regard to the objective quality measures. In addition, the proposed algorithm is less expensive than the state-of-the-art technology in terms of the resource requirements.