title: GD imagejpeg() compression?
body: <p>I'm working on a project where I edit the pixels of a jpg in PHP using the GD library.
  Its <strong>very crucial</strong> and key to my project that the output from PHP <strong>retains the pixel values</strong> I set (cough-steganography-cough).</p>
  
  <p>This is the first time I've attempted image manipulation in PHP. I've had no problems before in my Java implementations, so I was foolish not to investigate GD's <code>jpeg</code> compression quality before pursuing further.</p>
  
  <p>It turns out that after all my effort, my code does not function the way its supposed to. I am pretty sure it is not my code (tested the encode and decode functions on edited image resources and they worked).</p>
  
  <p><strong>My questions are:</strong></p>
  
  <ol>
  <li><p>The only problem I can see is with <code>imagejpeg()</code>'s compression. Could I be right?</p></li>
  <li><p>Are there any libraries that provide the compression that I need?(retain pixel values that I changed)</p></li>
  </ol>