title: ImageField won't delete file when using os.unlink()
body: <p>I have this model:</p>
  
  <pre><code>class UserProfile(models.Model):
      """(UserProfile description)"""
      user = models.ForeignKey(User)
      image = models.ImageField(upload_to=upload_to)
  
      def save(self):
          os.unlink(self.image.path)
          super(UserProfile, self).save()
  </code></pre>
  
  <p>The script fails on the <code>unlink()</code> method, and says the file cannot be found. Any ideas?</p>
  
  <p>The error says</p>
  
  <blockquote>
    <p>(2, 'No such file or directory')</p>
  </blockquote>