title: crop image (first 200px vertically) and save it php
body: <p>I have an image:</p>
  
  <p><code>/files/image.jpg</code></p>
  
  <p>this image has <code>1000x1000 px</code>.
  I want to crop and save it to has 800px vertically and keep the horizontal width (in example image 1000 but may change).</p>
  
  <p>Can anyone give me an example to use <code>imagecrop</code> or any function to this? and then save this file in <code>/files/image.jpg</code> replacing the original one?</p>