title: How to save an image to the photo gallery using Flutter?
body: <p>My flutter app uses the <a href="https://pub.dartlang.org/packages/camera" rel="noreferrer"><code>camera</code></a> package to take a photo, which I save to the application's data directory (obtained from <a href="https://pub.dartlang.org/packages/path_provider" rel="noreferrer"><code>path_provider</code></a> and the <code>getApplicationDocumentsDirectory()</code> function).</p>
  
  <p>How can I save this image file into the phone photo gallery? I've noticed the <a href="https://pub.dartlang.org/packages/image_picker" rel="noreferrer"><code>image_picker</code></a> package allows <em>reading</em> from the gallery, but how can I write to it? </p>