can anybody give suggestion to continue this code of inserting grayscale image into rgb image using dct

clear all;
close all;
clc
x=imread('hor.jpg');
figure
subplot(2,2,1)
imshow(x)
title('cover image x')

y=imread('dog.jpg');
subplot(2,2,2)
imshow(y)
title('image tobe hidden y')

z=imresize(y,[250 250]);
subplot(2,2,3)
imshow(z)
title('Reduced size of image tobe hidden z')

l=rgb2gray(z);
subplot(2,2,4)
imshow(l)
title('converted reduced sized image to graylevel l')

x1=x(:,:,1);figure;subplot(2,2,1);imshow(x1) 
title('Extracted Red component')

x2=x(:,:,2);subplot(2,2,2);imshow(x2)
title('Extracted green component')

x3=x(:,:,3);subplot(2,2,3);imshow(x3)
title('Extracted blue component')

dx1=dct2(x1);
dx2=dct2(x2);
dx3=dct2(x3);

figure
subplot(2,2,1)
imshow(dx1)
title('Applied dct to red channel') 

subplot(2,2,2)
imshow(dx2)
title('Applied dct to green channel')

subplot(2,2,3)
imshow(dx3)
title('Applied dct to blue channel')

% g=100;
% [rm,cm]=size(l);

[shivu P]

 i didnt get which part u edited