title: Tiff or Exif tag for BGRA
body: <p>I'm saving a BGRA image in a TIFF formatted file.<br>
  I need to save the data as-is without manipulation for recording and analysis purposes.  </p>
  
  <p>What tags do I need to set to tell the TIFF viewers that the data is stored as BGRA instead of the default RGBA ?<br>
  Currently image viewers just read the data as RGBA, and obviously all the colors are getting mangled.</p>