How do I save plot with specified x and y limits?

I am trying to plot a pattern but it is located in the middle of an image and it is very small so I adjusted the x and y limits to show a closer view. Here is a part of my code below:

 DP =fftshift(fft2(some_image));
 DM = abs(DP).^2;

 figure (1)
 imshow(DM)

 figure (2)
 b = zeros(2048);    % b is same with some_image, just with better resolution
 b(2048/2-256:2048/2+255,2048/2-256:2048/2+255) = DM(1:2:end,1:2:end);
 CD = abs(fftshift(fft2(b))).^2; 

 imagesc(CD)
 axis([2048/2-128 2048/2+127 2048/2-128 2048/2+127])
 imwrite(mat2gray(CD),'image.bmp')

The code worked fine but when I try to save the final image, it saved the image that is not axis adjusted. How do I save the executed image with a specified x and y limits?

Thanks,

[KSSV]

Try with saveas