title: DOMPDF images have poor quality when processing in server
body: <p>I am working on a website with different jQuery forms that output to a html result page, this html is converted to a pdf file with DOMPDF library. When the conversion is made in local, there is no problem, but when it takes place in the server, the resulting pdf images have lower quality than the originals, with white scratches and blur (I can upload an example if necessary).</p>
  
  <p>Doing some research, I tried the following solutions:<br>
  - tried different image formats (jpg, png, gif)<br>
  - tried different values for "DOMPDF_PDF_BACKEND" (rendering backend to use) (CPDF, PDFLib, GD)<br>
  - tried different "DOMPDF_DPI" values<br>
  - "DOMPDF_ENABLE_REMOTE" value is set to "true"<br>
  - tried opening the resulting pdf with different applications (ubuntu pdf viewer, adobe acrobat pdf, gimp, photoshop)</p>
  
  <p>all with the same result.
  <br><br></p>
  
  <p>Also took a look at phpinfo() both in local and server:</p>
  
  <p>PHP version<br>
  local:  PHP Version 5.5.11<br>
  server: PHP Version 5.3.29</p>
  
  <p>GD version:<br>
  both: bundled (2.1.0 compatible) <br></p>
  
  <p>GD FreeType Version :<br>
  local:   2.4.8 <br>
  version: 2.4.9</p>
  
  <p>libPNG Version:<br>
  local:  1.5.9 <br>
  server: 1.2.49 </p>
  
  <p><br>
  I don't know what other parameters to compare.</p>
  
  <p>I don't know what else to try.</p>
  
  <p>Thanks in advance.</p>