title: how to cut transparent part from photo with command or shell script
body: <p>I am having trouble to cut photos in the command line. I need to cut transparent part of a photo and save with command line or shell script
  Thanks beforehand. If I could do it I would apply it for 4000 photos and it would be a great help
  More clear explanation what I want to do
  I have a png picture like this
  <a href="https://i.stack.imgur.com/xqPSq.png" rel="noreferrer">enter image description here</a></p>
  
  <p>I want to have an image like this</p>
  
  <p><a href="https://i.stack.imgur.com/ArMyh.png" rel="noreferrer">enter image description here</a></p>
  
  <p>I could make the image transparent only and is there any way to cut bottom transparent part from a png file</p>
  
  <p>Beforehand thank you very much</p>