title: What does reshape(60000, 28, 28, 1) mean?
body: <p>I'm learning convolutional networks and python all at once.</p>
  
  <p>I have a problem with the following code:</p>
  
  <pre><code>import tensorflow as tf
  print(tf.__version__)
  mnist = tf.keras.datasets.fashion_mnist
  (training_images, training_labels), (test_images, test_labels) = mnist.load_data()
  training_images=training_images.reshape(60000, 28, 28, 1)
  </code></pre>
  
  <p>I don't understand what <code>reshape(60000, 28, 28, 1)</code> means.</p>
  
  <p>What are 60000 and 28 and 28 and 1?</p>
  
  <p>I will get 60000 arrays of 28 columns by 28 rows... and the 1 is...</p>