Django Order By Empty Value Count

Add a property or a function that will count the total number of pictures for you:

# Calculate non-empty fields count
class Picture(models.Model):
    picture1 = models.CharField(help_text="picture 1", max_length=255, blank=True)  
    picture2 = models.CharField(help_text="picture 2", max_length=255, blank=True)
    # save it to the database
    non_empty_fields = property(picture_count)

    def picture_count(self):
        fields = self._meta.get_fields()
        n_count = len([ x for x in fields if getattr(self, field.name) ])
        return n_count  

    class Meta:
        ordering = ('picture_count', '-id')