title: PHP Imagick Class - Convert JPEG's to Progressive JPEG's? Interlace not working
body: <p>I'm trying to finish up my image uploader that utilizes imagick for the handling of various image types. One thing specifically that I'm trying to get working is the conversion of jpeg files to progressive jpeg. I've tried the following code below, but when I view the images that get output in irfranview, the jpeg are not progressive. Any ideas?</p>
  
  <pre><code>foreach ($thumbnailScaleWidths as $thumbnailScaleWidth) {
      $thumbnail = new imagick($uploadedFile['tmp_name']);
      $thumbnailDimensions = $thumbnail-&gt;getImageGeometry();
      $thumbnailWidth = $thumbnailDimensions['width'];
      $thumbnailHeight = $thumbnailDimensions['height'];
      $thumbnailScaleHeight = ($thumbnailScaleWidth / $thumbnailWidth) * $thumbnailHeight;
  
      $thumbnail-&gt;thumbnailImage($thumbnailScaleWidth, $thumbnailScaleHeight);
      $thumbnail-&gt;setImageInterlaceScheme(Imagick::INTERLACE_PLANE);
      $thumbnail-&gt;writeImages($_SERVER['DOCUMENT_ROOT'] . "/Resources/Media/$userId/$internalName-$thumbnailScaleWidth.$fileType", true);
  }
  </code></pre>
  
  <p>Any ideas as to why this isn't outputting progressive jpegs?</p>