title: How to lighten an image using ImageMagick like when using compare?
body: <p>As you see in the answer <a href="https://stackoverflow.com/a/11362152/1366368">“Diff” an image using ImageMagick</a>, the "delta" image is somehow lightened:</p>
  
  <p><img src="https://i.stack.imgur.com/bunXr.png" alt="enter image description here"></p>
  
  <p>How would I lighten an image just like that using ImageMagick?</p>