title: Keras - pad tensor with values on the borders
body: <p>I have image with size that's not even, so when convolution scales it down by a factor of 2, and then I do <code>Conv2DTranspose</code>, I don't get consistent sizes, which is a problem. </p>
  
  <p>So I thought I'd pad the intermediate tensor with an extra row and column, with values same as what I see on the edges, for minimal disruption. How do I do this in Keras, is it even possible? What are my alternatives?</p>