title: resize and pad numpy array with additional dimensions
body: <p>I have an np array with shape <code>(100,28,28)</code></p>
  <p>I would like to turn it to <code>(100,32,32,3)</code></p>
  <p>by padding with zero's and adding dimensions</p>
  <p>I tried np.newaxis which got me as far as <code>(100,28,28,1)</code></p>