title: How to correct the shape of Y_labels images
body: <p>An image in GrayScale has <code>(H, W)</code> shape, although, an image RGB has <code>(H, W, C)</code> shape <code>(C: channels)</code>. </p>
  
  <p>When a <strong>Gray</strong> image (called on the code to <strong>DEPTH</strong>) is loaded, I had the shape <code>(128, 128)</code> and can show this picture, with the format:</p>
  
  <pre><code>[[0 0 0 ... 0 0 0]
   [0 0 0 ... 0 0 0]
   [0 0 0 ... 0 0 0]
   ...
   [2 1 0 ... 0 0 0]
   [0 0 0 ... 0 0 0]
   [0 0 0 ... 0 0 0]]
  </code></pre>
  
  <p>The same way, when an <strong>RGB image</strong> (called just <strong>IMAGE</strong>) is loaded, I had the shape <code>(128, 128, 3)</code> and can show this picture, with the format:</p>
  
  <pre><code>[[[21 34 27]
    [25 37 33]
    [26 37 33]
    ...
    [28 38 50]
    [18 20 20]
    [30 29 12]]
   ...
   [[20 30 33]
    [23 34 35]
    [23 35 35]
    ...
    [31 24  7]
    [34 29  1]
    [35 29  8]]]
  </code></pre>
  
  <p>How can I do to have the shape <code>(W, H, C)</code> in the Gray Image like an RGB Image? </p>
  
  <p>If I reshape (using np.reshape or resize) adding just a last channel, broken the image and I can't show or use it. The image reshaped has a form <code>(128, 128, 1)</code></p>
  
  <pre><code>[[[0]
    [0]
    [0]
    ...
    [0]
    [0]
    [0]]
   ...
   [[2]
    [1]
    [0]
    ...
    [0]
    [0]
    [0]]
  </code></pre>
  
  <hr>
  
  <pre><code>Y_train = np.zeros((len(images), IMG_HEIGHT, IMG_WIDTH, 1), dtype=np.int8)
  mask = np.zeros((IMG_HEIGHT, IMG_WIDTH, 1), dtype=np.int8)
  for i in tqdm(range(len(depths))):
  &amp;emsp;mask = imread(depths[i])
  &amp;emsp;mask = resize(mask, (IMG_HEIGHT, IMG_WIDTH), mode='constant', preserve_range=True)
  &amp;emsp;Y_train[i] = mask
  print(Y_train[0].shape)
  print(Y_train[0])
  imshow(Y_train[0]) #-- SUCCESFULL TO PRINT
  </code></pre>
  
  <p></p>
  
  <pre><code>test = np.resize(test, (IMG_HEIGHT, IMG_WIDTH, 1))
  print(test.shape)
  print(test)
  imshow(test) #-- FAIL TO PRINT
  </code></pre>