title: How to square an image and pad with transparency from the commandline (imagemagick)
body: <p>The section entitled <a href="http://www.imagemagick.org/Usage/thumbnails/#square" rel="noreferrer">Square Padding or Cropping</a> describes a method to generate a square image--for a file whose dimensions are unknown--and pad the background with a color.</p>
  
  <p>How do I perform the same operation, but create a <strong>transparent</strong> background.</p>