title: QML Check if file/image exists before getting the error
body: <p>I want to check if an image exists in the local directory, and if not, load a default one. I found a workout by using:</p>
  
  <pre><code>    Image {
          id: image
          source: source1
          onStatusChanged: {
              if ( (image.status == Image.Error) &amp;&amp; source !== default_source ) {
                  source = default_source
              }
          }
      }
  </code></pre>
  
  <p>But I would prefer to test if the file exists before getting the error. Is there any cleaner way to test file_paths/url/images before trying to load them?</p>
  
  <p>Thanks!</p>