Django изменить изображение профиля по умолчанию по полу

Question

Я хочу изменить изображение профиля по умолчанию в зависимости от пола. Я выбираю Мужской в ​​форме регистрации, но всегда отображаю «default_f.png».

models.py

    GENDER_CATEGORY = (
    ('U','Undefined'),
    ('F','Female'),
    ('M','Male')
                    )
class Profile(models.Model):
    user = models.OneToOneField(User,on_delete=models.CASCADE)
    image = models.ImageField(upload_to="profile_pics",verbose_name="")
    cover_image = models.ImageField(default="default_cover.jpg",upload_to="cover_pics",verbose_name="")
    bio = models.CharField(max_length=160,null=True,blank=True)
    location = models.CharField(max_length=30,null=True,blank=True)
    birth_date = models.DateField(null=True,blank=True)
    follow = models.ManyToManyField(User,related_name="follower")
    date_created = models.DateTimeField(default=timezone.now)
    gender = models.CharField(choices=GENDER_CATEGORY,max_length=2)

Сигналы

Поэтому я пробую это выражение if, но всегда показываю default_f.png. Я изменяю pre_save на post_save, но он не меняется.

  def post_save_avatar(sender, instance, *args, **kwargs):
    if not instance.image:
        if instance.gender == 'M':
            instance.image="default_m.jpg"
        else:
            instance.image = "default_f.png"
        print(instance.gender)
pre_save.connect(post_save_avatar, sender=Profile)




def create_profile(sender, **kwargs):
    if kwargs['created']:
        user_profile = Profile.objects.create(user=kwargs['instance'])

post_save.connect(create_profile,sender=User)

forms.py

class RegisterForm(UserCreationForm):
    email = forms.EmailField()
    class Meta:
        model = User
        fields = ('username','email','password1','password2')

class ProfileRegisterForm(forms.ModelForm):
    class Meta:
        model = Profile
        fields = ['bio','gender']

views.py

def register(request):
    if request.method == "POST":
        form = RegisterForm(request.POST)
        p_form = ProfileRegisterForm(request.POST)
        if form.is_valid() and p_form.is_valid():
            user = form.save()
            user.refresh_from_db()#load the profile instance create by the signal
            p_form = ProfileRegisterForm(request.POST,instance=user.profile)
            p_form.full_clean()
            p_form.save()
            # username = form.cleaned_data.get('username')
            return redirect('login')
    else:
        form = RegisterForm()
        p_form = ProfileRegisterForm()
    context = {
    'form':form,
    'p_form':p_form
    }
        fields = ['bio','gender']