Django: Create ImageField thumbnail

admin.py

from pathlib import PosixPath

from django import forms
from django.conf import settings
from django.contrib import admin

from my_app.models import Item


class ItemForm(forms.ModelForm):
    logo_name = forms.CharField(
        widget=forms.HiddenInput(),
        required=False,
    )
    
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        if self.instance.logo:
            self.fields["logo_name"].initial = self.instance.logo.name

    class Meta:
        model = Item
        
        
class ItemAdmin(admin.ModelAdmin):
    def response_change(self, request, obj):
        """Delete logo file when clear-checkbox is on."""
        if request.POST.get("logo-clear") == "on":
            # settings.MEDIA_ROOT: pathlib.PosixPath
            logo_file = settings.MEDIA_ROOT / request.POST["logo_name"]
            logo_file.unlink(missing_ok=True)
        return super().response_change(request, obj)

models.py

from io import BytesIO
from pathlib import PurePath
from typing import NamedTuple
from uuid import uuid4

from PIL import Image

from django.core.files import File
from django.db import models


class ImageSize(NamedTuple):
    height: int = 150
    width: int = 150

        
def logo_upload_path(instance, filename):
    """For logo."""
    if instance.logo and instance.logo.name.startswith("item_thumbnails/"):
        return instance.logo.name
    filename_p = PurePath(filename)
    return f"item_thumbnails/{uuid4().hex}{filename_p.suffix}"


class Item(models.Model):
    logo = models.ImageField("logo", blank=True, default=None)
    
    THUMBNAIL_SIZE = ImageSize(height=150, width=150)
    
    def _create_thumbnail(self):
        if not self.logo:
            return

        if self.logo.height <= self.THUMBNAIL_SIZE.height and self.logo.width <= self.THUMBNAIL_SIZE.width:
            return
        
        self.logo.open()
        logo_buf = BytesIO(self.logo.read())
        self.logo.close()

        image = Image.open(logo_buf)
        image.thumbnail(self.THUMBNAIL_SIZE, Image.ANTIALIAS)
        thumbnail_buf = BytesIO()
        image.save(thumbnail_buf, image.format)

        thumbnail_buf.seek(0)
        file = File(thumbnail_buf, name=logo_upload_path(self, self.logo.name))
        self.logo.file = file
        self.logo.name = file.name

    def save(self, *args, **kwargs):
        self._create_thumbnail()
        super().save(*args, **kwargs)