title: Add border/outline to a transparent (png) image with ImageMagick
body: <p>I try to add border to a transparent png image, and <a href="http://www.imagemagick.org/discourse-server/viewtopic.php?t=16399" rel="nofollow noreferrer">I found some solutions</a>.</p>
  
  <p>But my problem is I can't increase the image size in the same amount like the border size.</p>
  
  <p>Currently I use this code:</p>
  
  <pre><code>convert stone.png -bordercolor none -border 15 /
  -background red -alpha background -channel A -blur 15x15 -level 0,0% result.png
  </code></pre>
  
  <p>First I create a transparent border to increase the image size, and it's works fine. But when I try to add the visible border with the <code>blur</code> command, I can't figure out, what parameter I should use, to set a border, what will have the size like my "transparent border".</p>
  
  <p>original image:</p>
  
  <p><img src="https://i.stack.imgur.com/KPEgz.png" alt="original image"></p>
  
  <p>my result with the code above:</p>
  
  <p><img src="https://i.stack.imgur.com/pS1EV.png" alt="my result of the image"></p>
  
  <p>As you can see, the bottom corners are cutted. They should be rounded.</p>