How to arrange stacked Images into a 2 dimension array?

I have a stack of 40 Images with dimension of 1000*1000 as:

Images<1000*1000*40 double>

I want to arrange the Images as shown below in a single array of size 8000*5000:

Can anyone help?

[David Young]

It is very helpful that the question has been asked so clearly.

Answer 1

[David Young]

Images2d = reshape( ...
               permute( ...
                   reshape(Images, 1000, 1000, 8, 5), ...
               [1 3 2 4]), ...
           8000, 5000);

Answer 2

[Walter Roberson]

You can mat2cell splitting along the 3rd dimension, reshape the cell array 8x5 and then cell2mat back

[Walter Roberson]

Sz = size(Image4D);
T = mat2cell(Image4D, Sz(1), Sz(2), Sz(3), ones(1,Sz(4));
Image3D = cell2mat(reshape(T, 8, 5));