old_contents: # Django
  from django.db import models
  
  # AstroBin
  from astrobin.models import Image
  
  class ThumbnailGroup(models.Model):
      image = models.ForeignKey(
          Image,
          related_name = 'thumbnails',
      )
  
      revision = models.CharField(
          max_length = 1,
          default = '0',
      )
  
      real             = models.CharField(max_length = 512, null = True, blank = True)
      real_inverted    = models.CharField(max_length = 512, null = True, blank = True)
      hd               = models.CharField(max_length = 512, null = True, blank = True)
      hd_inverted      = models.CharField(max_length = 512, null = True, blank = True)
      regular          = models.CharField(max_length = 512, null = True, blank = True)
      regular_inverted = models.CharField(max_length = 512, null = True, blank = True)
      gallery          = models.CharField(max_length = 512, null = True, blank = True)
      gallery_inverted = models.CharField(max_length = 512, null = True, blank = True)
      thumb            = models.CharField(max_length = 512, null = True, blank = True)
      revision         = models.CharField(max_length = 512, null = True, blank = True)
      histogram        = models.CharField(max_length = 512, null = True, blank = True)
      iotd             = models.CharField(max_length = 512, null = True, blank = True)
      act_target       = models.CharField(max_length = 512, null = True, blank = True)
      act_object       = models.CharField(max_length = 512, null = True, blank = True)
  
      def __unicode__(self):
          return "Thumbnails for image " % image.title
  
      class Meta:
          app_label = 'astrobin_apps_images'
          unique_together = ('image', 'revision',)
  
  
new_contents: # Django
  from django.db import models
  
  # AstroBin
  from astrobin.models import Image
  
  class ThumbnailGroup(models.Model):
      image = models.ForeignKey(
          Image,
          related_name = 'thumbnails',
      )
  
      revision = models.CharField(
          max_length = 1,
          default = '0',
      )
  
      real             = models.CharField(max_length = 512, null = True, blank = True)
      real_inverted    = models.CharField(max_length = 512, null = True, blank = True)
      hd               = models.CharField(max_length = 512, null = True, blank = True)
      hd_inverted      = models.CharField(max_length = 512, null = True, blank = True)
      regular          = models.CharField(max_length = 512, null = True, blank = True)
      regular_inverted = models.CharField(max_length = 512, null = True, blank = True)
      gallery          = models.CharField(max_length = 512, null = True, blank = True)
      gallery_inverted = models.CharField(max_length = 512, null = True, blank = True)
      thumb            = models.CharField(max_length = 512, null = True, blank = True)
      revision         = models.CharField(max_length = 512, null = True, blank = True)
      histogram        = models.CharField(max_length = 512, null = True, blank = True)
      iotd             = models.CharField(max_length = 512, null = True, blank = True)
      act_target       = models.CharField(max_length = 512, null = True, blank = True)
      act_object       = models.CharField(max_length = 512, null = True, blank = True)
  
      def __unicode__(self):
          return "Thumbnails for image " % self.image.title
  
      class Meta:
          app_label = 'astrobin_apps_images'
          unique_together = ('image', 'revision',)
  
  
subject: Add self.