title: PhantomJS renders different rasterized images on 2 servers with same version
body: <p>I use PhantomJS 1.9.8 to generate PNG thumbnails from SVG documents, with a script similar to <a href="https://github.com/ariya/phantomjs/blob/master/examples/rasterize.js" rel="nofollow">the one provided by PhantomJS</a>. I have created a test a few months ago to check that the rendered image is the one that I expect. Today this test fails. There were probably some Debian packages that changed on the server on which these tests are done, but I didn't change the PhantomJS (which I run as a static binary) and I've read that PhantomJS is not supposed to have any external dependencies.</p>
  
  <p>The two images look very similar but as I check their binary content the test just fails :</p>
  
  <p><a href="http://i.stack.imgur.com/8GC8n.png" rel="nofollow">Expected image</a></p>
  
  <p><a href="http://i.stack.imgur.com/FqFXL.png" rel="nofollow">Actual image</a></p>
  
  <p>What explains this difference ? On my local environment the test still succeeds.</p>