title: Django Form Imagefield validation for certain width and height
body: <p>I am trying to validate the image dimension in form level and display a message to user if submitted photo does not meet requirement which is image dimension 1080x1920. I dont want to store the width and height size in database. I tried with the Imagefield width and height attribute. But it is not working.</p>
  
  <pre><code>class Adv(models.Model):
  
      image = models.ImageField(upload_to=r'photos/%Y/%m/',
          width_field = ?,
          height_field = ?,
          help_text='Image size: Width=1080 pixel. Height=1920 pixel',
  </code></pre>