Steganography (or Data Concealing, Data Masking, or Data Hiding) is the art of concealing information within other data, structures, or media to avoid detection or access by unauthorized users. Various domains and contexts can be used to hide data. By hiding sensitive data, you can prevent unauthorized access, tampering, or theft, protect your privacy, or even protect your intellectual property. Using images as cover media is the most effective method of steganography. A new method based on the modified technique described by the authors for grayscale images is presented in this manuscript for comparing the color images performance. Data can be hidden in color images by blocking them. Our calculation of the detail coefficients of the secret image uses an approximation of the blue, green, and red components of the cover image. As an alternative to block coefficients, we substitute approximation coefficients for root mean square errors. The best matching blocks are stored using a key. A single image hides a large amount of data, so the work is expected to be successful. A better peak signal-to-noise ratio is provided by Stego Medical Image (StMdIg).