How can I annotate a Django queryset with a count in a way that's conditional to some property of each item in the queryset? -

sorry title, think pseudo-code clarify question:

class image(model):     user = foreignkey(user)  class group(model):     members = foreignkey(user)     images = foreignkey(image)     autosubmission = booleanfield() 

as can see, have group, consisting of members , images.

if group autosubmission members don't submit images manually it, images belonging member automatically show in group.

if group not autosubmission members need submit images manually, , end in images foreignkey.

now, want have queryset that's annotated number of images the group.

group.objects.all().annotate(num_images = count('images')) 

obviously, code above works groups not autosubmission, i.e. images in images relation.

so how can annotate queryset works both groups autosubmission , groups not?

thanks!