how to change image format when uploading image in django?

Question

When a user uploads an image from the Django admin panel, I want to change the image format to ‘.webp’. I have overridden the save method of the model. Webp file is generated in the media/banner folder but the generated file is not saved in the database. How can I achieve that?

def save(self, *args, **kwargs):
    super(Banner, self).save(*args, **kwargs)
    im = Image.open(self.image.path).convert('RGB')
    name = 'Some File Name with .webp extention' 
    im.save(name, 'webp')
    self.image = im

But After saving the model, instance of the Image class not saved in the database?

My Model Class is :

class Banner(models.Model):
    image = models.ImageField(upload_to='banner')
    device_size = models.CharField(max_length=20, choices=Banner_Device_Choice)

Asked By: Manoj Kamble

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Source

Answer 1

from django.core.files import ContentFile

If you already have the webp file, read the webp file, put it into the ContentFile() with a buffer (something like io.BytesIO). Then you can proceed to save the ContentFile() object to a model. Do not forget to update the model field, and save the model!

https://docs.djangoproject.com/en/4.1/ref/files/file/

Alternatively

"django-webp-converter is a Django app which straightforwardly converts static images to WebP images, falling back to the original static image for unsupported browsers."

It might have some save capabilities too.

https://django-webp-converter.readthedocs.io/en/latest/

The cause

You are also saving in the wrong order, the correct order to call the super().save() is at the end.

Edited, and tested solution:

from django.core.files import ContentFile
from io import BytesIO

def save(self, *args, **kwargs):
    #if not self.pk: #Assuming you don't want to do this literally every time an object is saved.
    img_io = BytesIO()
    im = Image.open(self.image).convert('RGB')
    im.save(img_io, format='WEBP')
    name="this_is_my_webp_file.webp"
    self.image = ContentFile(img_io.getvalue(), name)
    super(Banner, self).save(*args, **kwargs) #Not at start  anymore

Answered By: nigel239

Answer 2

hello do it like this:

...
from django.db.models.signals import post_save
from django.dispatch import receiver

class Banner(models.Model):
    image = models.ImageField(upload_to='banner')
    device_size = models.CharField(max_length=20,choices=Banner_Device_Choice)
        
            
@receiver(post_save, sender=Banner)
def create_webp(sender, instance, created, **kwargs):
    path = instance.image.path
    if instance.image.path[-4:] !=webp:
        im = Image.open(path).convert('RGB')
        extention = instance.image.path.rsplit(".",2)[1]
        file_name = path.replace(extention,"webp") 
        im.save(file_name, 'webp')
        instance.image.path = file_name
        instance.save()

Answered By: Xeus

how to change image format when uploading image in django?

Question:

Answers:

Alternatively

The cause

Edited, and tested solution: