title: How to change the filter of an image in a PDF file
body: <p>I'm building a tool to compress PDF files, and using pdfbox.
  I have some images with the <code>DCTDecode</code> + <code>FlateDecode</code> filter and I'd like to experiment with the <code>JPXDecode</code> filter to see if it occupies less space.</p>
  
  <p>I've seen some code using <a href="https://stackoverflow.com/questions/20614350/compress-pdf-with-large-images-via-java"><code>iText</code></a>, but how to do it with <code>pdfbox</code>?.  I've found no documentation how to do so.</p>