title: blueimp / jQuery-File-Upload Thumbnails not working
body: <p>I just installed <a href="http://blueimp.github.io/jQuery-File-Upload/" rel="nofollow">jQuery-File-Upload</a> and I was testing demo on my raspberry pi (apache2), upload works but there is error message <code>Failed to create scaled version: thumbnail</code> I didn't change anything in files so where is the problem?</p>
  
  <p>I also tested same demo on XAMPP and there was working fine</p>