title: Convert Transparent PNG to JPG with Non-Black Background Color
body: <p>I'm using System.Drawing.Image in .Net to do a simple conversion from png to jpeg. 
  I'm basically just using these two lines of code:</p>
  
  <pre><code>Image img = Image.FromFile(filename);
  img.Save(newFilename, System.Drawing.Imaging.ImageFormat.Jpeg);
  </code></pre>
  
  <p>it works fine except for when the png files contain transparency due to the alpha channel. In which case the converted jpeg has a black background. Is there any way to make the background white instead?</p>