fields.py

import io
import os

from django.core.files import File
from django.core.exceptions import ValidationError
from django.db import models
from PIL import Image, ImageOps


class AdvanceThumbnailField(models.ImageField):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

    def contribute_to_class(self, cls, name, **kwargs):
        super().contribute_to_class(cls, name, **kwargs)
        models.signals.post_save.connect(self.convert_to_webp, sender=cls)
        models.signals.pre_delete.connect(self.delete_image, sender=cls)
        models.signals.pre_save.connect(self.auto_delete_file_on_change, sender=cls)

    def pre_save(self, model_instance, add):
        file = super().pre_save(model_instance, add)
        if not file:
            file.delete(save=False)
        return file

    def convert_to_webp(self, instance, **kwargs):
        image_field = getattr(instance, self.name)
        if not image_field or not image_field.name:
            return

        models.signals.post_save.disconnect(
            self.convert_to_webp, sender=instance.__class__
        )

        try:
            with image_field.open() as source_file:
                img = Image.open(source_file)
                img = ImageOps.exif_transpose(img)

                webp_io = io.BytesIO()
                img.save(webp_io, format="WEBP")
                webp_io.seek(0)

                base_name = os.path.basename(
                    image_field.name
                )  
                name, _ = os.path.splitext(base_name)  
                name = f"{name}.webp"

                image_field.delete(save=False)
                webp_file = File(webp_io, name=name)
                setattr(instance, self.name, webp_file)
                instance.save(update_fields=[self.name])
        finally:
            models.signals.post_save.connect(
                self.convert_to_webp, sender=instance.__class__
            )

    def delete_image(self, instance, **kwargs):
        if instance.image:
            image_path = instance.image.path
            if os.path.exists(image_path):
                os.remove(image_path)
            else:
                pass

    def auto_delete_file_on_change(self, instance, **kwargs):
        if not instance.pk:
            return False

        try:
            old_instance = instance.__class__.objects.get(pk=instance.pk)
            old_file = getattr(old_instance, self.name)
            if not old_file:
                return False
        except instance.__class__.DoesNotExist:
            return False
        new_file = getattr(instance, self.name)
        print(old_file.path, new_file.path)
        if old_file and new_file and old_file != new_file:
            old_file_path = old_file.path if old_file else None
            new_file_path = new_file.path if new_file else None

            if (
                old_file_path
                and old_file_path != new_file_path
                and os.path.isfile(old_file_path)
            ):
                os.remove(old_file_path)

        return False