title: When should I use PixelFormats.Pbgra32 in WPF application?
body: <p>Consider following setup: I have some images on disk. I cannot modify those images since they belong to another project. I just read them.</p>
  
  <p>I need them processed to look optimal in my app. I mean pixel shader processed.
  When I'm done with processing, the output image will be used as a thumbnail in some sort of ListView or other control.</p>
  
  <p>I chose <code>PixelFormats.Bgra32</code> as the output format, because it's pretty straightforward to build pixel shader for it.
  I read however <code>PixelFormats.Pbgra32</code> is natively used by Windows and thus is faster.</p>
  
  <p>Is it still faster, when fade effects are used on the image? Does it make sense to pre-multiply channels in managed code instead leaving this to the framework?</p>