myImage = rand(64,48);
x = 1:3:64;
y = 1:3:48;
[X,Y] = meshgrid(x,y);
subImages = arrayfun( @(x,y) myImage(x:min(end,x+3),y:min(end,y+3)), X, Y, 'UniformOutput', false )';
should give you a cell array containing 4*4 overlapping sub-images upto the final one which may be smaller due to the image size.
I tested that in a bit of a rush though so there may be some elements not quite right. Hopefully it gives you an idea though if it isn't a complete answer.
