title: how to set height only when resizing using ImageMagick
body: <p>The following code resizes an image so that its width is 200 and its height is whatever...
  How would I do it so that the height was 200 and the width was whatever...</p>
  
  <p>$command = MAGICK_PATH."convert ".$filename." -resize 200 ".$filename;
  exec($command);</p>
  
  <p>Kind regards J</p>