title: Down-sample mri T1 image in python with Nipy
body: <p>I have a T1 image (NIFTI), already aligned, with dimension 121 x 145 x 121.<br>
  The image is loaded by nibabel. The voxel size is 1.5 x 1.5 x 1.5 mm.<br>
  I want to down-sample it to an image with 2.0 x 2.0 x 2.0 mm resolution and keep the images aligned.</p>
  
  <p>I have little knowledge in MRI image manipulation.
  I couldn't find a clear tutorial.</p>
  
  <p>How do I do that ?
  If you know any other Python library that can do it, it would also work.</p>