title: Keras getting wrong output shape
body: <p>For the following CNN </p>
  
  <pre><code>model = Sequential()
  model.add(Convolution2D(64, 3, 3, border_mode='same', input_shape=(3, 256, 256)))
  # now model.output_shape == (None, 64, 256, 256)
  
  # add a 3x3 convolution on top, with 32 output filters:
  model.add(Convolution2D(32, 3, 3, border_mode='same'))
  # now model.output_shape == (None, 32, 256, 256)
  print(model.summary())
  </code></pre>
  
  <p>However model summary gives the following output</p>
  
  <pre><code>____________________________________________________________________________________________________
  Layer (type)                     Output Shape          Param #     Connected to                     
  ====================================================================================================
  convolution2d_44 (Convolution2D) (None, 3, 256, 64)    147520      convolution2d_input_24[0][0]     
  ____________________________________________________________________________________________________
  convolution2d_45 (Convolution2D) (None, 3, 256, 32)    18464       convolution2d_44[0][0]           
  ====================================================================================================
  Total params: 165984
  </code></pre>
  
  <p>Why am i getting the given output shape ?</p>