Patch image using mat2tiles and back to original image

I used the Mat2tiles function for patching the input image, but how do I combine the patch images back to the original image?

My code is like this.

close all;
clear all;
img = imread('rice.png');
patches = mat2tiles(img,[64,64]);
[m n] = size(patches);
i = m * n;
for j = 1:i
    b = patches{j};
    figure,imshow(patches{j});
    file_B = strcat('F:\IMG',num2str(j),'.png');
    imwrite(b,file_B);
end