title: What is the difference between: image/x-citrix-pjpeg and image/pjpeg
body: <p>Some files are uploaded with a reported MIME type:</p>
  
  <pre><code>image/x-citrix-pjpeg
  </code></pre>
  
  <p>They are valid jpeg files and I accept them as such.</p>
  
  <p>I was wondering however: why is the MIME type different?<br>
  Is there any difference in the format? or was this mimetype invented by some light bulb at citrix for no apparent reason?</p>