title: KIVY: Image in Button is stretched
body: <p>I am using the background_normal for setting image to a button, but the result is that the image is stretched. </p>
  
  <pre><code>Button:
          background_normal:'this.jpg'
  </code></pre>
  
  <p>Is there a way to have a center aligned image inside the button. Also please tell me how we'd do it in python. </p>