original = imread('koala.jpg'); %read in original RGB image

gray = rgb2gray(original); %convert to grayscale

imwrite(gray,'gray.jpg'); %write to new image

backtorgb = cat(3,gray,gray,gray); %convert to RGB format without color

imwrite(backtorgb,'backtorgb.jpg'); %write to new image

Hello Jeffrey,

Thank You Very much

Try doing this

gray = rgb2gray(original,[]); // to avoid any saturation issues