how to write zoom code with scale for an rgb image

i write this one for gray image but i looking for rgb's too (nearest neighbor)

I1=[50 80 100 ; 115 21 90 ;32 50 160];
S=2 ;
[M , N]=size(I1);
M2=S*M;
N2=S*N;
I2=zeros(M2 , N2);
for i =1:M2 
    for j = 1:N2
        x =i/S;
        y=j/S;
        x2=round(x);
        y2=round(y);
        if (x2<1)||(x2>M)||(y2<1)||(y2>N)
    I2(i , j)=0;
else
    I2(i,j)=I1(x2 ,y2);
end
    end

end

Answer 1

[Walter Roberson]

for Channel = 1 : 3
 I1 = YourImage(:,:,Channel)
 now do the zooming here, just like above except without the assignment to I1
 I3(:, :, Channel) = I2;
end

[alireza kooshafar]

tnx i get the way but not this part''except without the assignment to I1''

[Walter Roberson]

Your very first line was

I1=[50 80 100 ; 115 21 90 ;32 50 160];

Omit that line completely. Instead, before the loop, initialize YourImage to be an appropriate RGB image.