image_upload.py

# This is the code to resize images on upload with Django Python. Works with both local files and cloud storages like S3.
import PIL
from django.db import models
from django.utils.translation import gettext_lazy as _


class Image(models.Model):
  name = models.CharField(_("Name"), max_length=254)
  image = models.ImageField(_("Image"), upload_to="images", blank=True, null=True)
  
  def __str__(self) -> str:
    return self.name
  
  def save(self, *args, **kwargs) -> None:
    super().save(*args, **kwargs)
    img = PIL.Image.open(self.image)
    width, height = img.size
    target_width = 600
    h_coefficient = width/600
    target_height = height/h_coefficient
    img = img.resize((int(target_width), int(target_height)), PIL.Image.ANTIALIASING)
    img.save(self.image.path, qulatity=100)
    img.close()
    self.image.close()