Django query annotation with boolean field

I eventually found a way to do this using django 1.8's new conditional expressions:

from django.db.models import Case, When, Value, IntegerField
q = (
    Product.objects
           .filter(...)
           .annotate(image_count=Count('images'))
           .annotate(
               have_images=Case(
                   When(image_count__gt=0,
                        then=Value(1)),
                   default=Value(0),
                   output_field=IntegerField()))
           .order_by('-have_images')
)

And that's how I finally found incentive to upgrade to 1.8 from 1.7.

As from Django 1.11 it is possible to use Exists. Example below comes from Exists documentation:

>>> from django.db.models import Exists, OuterRef
>>> from datetime import timedelta
>>> from django.utils import timezone
>>> one_day_ago = timezone.now() - timedelta(days=1)
>>> recent_comments = Comment.objects.filter(
...     post=OuterRef('pk'),
...     created_at__gte=one_day_ago,
... )
>>> Post.objects.annotate(recent_comment=Exists(recent_comments))