How to increase slice thickness?

Hi I reconstruct the three planes using the below code. As you can see, when run it, it comes up with 2 thin bars of the sagittal and coronal planes. I want to expand them. Not being too thin. Imresize does not work, 'cause, it just expands the width of the pixels, making it look like a distorted one and keeps the same column-bar size. I want a bigger bar size. How do I do that?

D=squeeze(D); Ds=smooth3(D);

figure, imshow(Ds(:,:,N),[]); %transverse plane title ('Axial Plane');

figure, imshow(squeeze(Ds(:,N,:)),[]'); %sagittal plane title ('Sagittal Plane');

figure, imshow(squeeze(Ds(N,:,:)),[]); % coronal plane title('Coronal Plane')