title: Can't upload user picture
body: <p>I want to upload an image for a simply user on the default form and I get the following error :</p>
  
  <blockquote>
    <p>"The file could not be uploaded."</p>
  </blockquote>
  
  <p>I have tried with all types of file formats.</p>
  
  <p>I also checked the rights to the directory :</p>
  
  <blockquote>
    <p>sites/default/files</p>
  </blockquote>