How to limit image upload size in Django?

Question

Django

Good afternoon. Trying to make a simple limited image uploader. I've been trying to solve this problem for 2 days, but so far nothing

Question 1: How can I limit the uploaded object to 200 kb?

My attempts:

models.py

class UploadImage(models.Model):
    title = models.CharField(max_length=100, unique=True, verbose_name='Введите название изображения')
    cover = models.ImageField(upload_to='images/', verbose_name='')

    def __str__(self):
        return self.title

forms.py

class PostForm(forms.ModelForm):
    class Meta:
        model = UploadImage
        fields = ['title', 'cover']

    def clean_image(self):
        cover = self.cleaned_data.get('cover', False)
        if cover:
            if cover.size > 4*1024*1024:
                raise ValidationError("Image file too large ( > 4mb )")
            return cover
        else:
            raise ValidationError("Couldn't read uploaded image")

For some reason, this method does not work, although here we are talking about 4mb

2. How to refer to the message object from the view?

views.py

class IndexView(LoginRequiredMixin, CreateView):
    template_name = 'upload/index.html'
    form_class = PostForm
    model = UploadImage
    success_url = '/upload/'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['message'] = ''
        return context

I want to create an informational message in the same form check if the form worked correctly or not.
Tried something like this:

if 1 + 2 == 3:
   IndexView.get_context_data(self, message) = 'Всё верно'
else:
    IndexView.get_context_data(self, message) = 'Неверно'

Answer 1

1. clean_image is clean image fields