[ACCEPTED]-Django / PIL - save thumbnail version right when image is uploaded-pillow

Based on xjtian's answer. This works for 1 Python 3:

import os.path
from PIL import Image
from io import BytesIO
from django.core.files.base import ContentFile
from .my_app_settings import THUMB_SIZE    

class Photo(models.Model):
    photo = models.ImageField(upload_to='photos')
    thumbnail = models.ImageField(upload_to='thumbs', editable=False)

    def save(self, *args, **kwargs):

        if not self.make_thumbnail():
            # set to a default thumbnail
            raise Exception('Could not create thumbnail - is the file type valid?')

        super(Photo, self).save(*args, **kwargs)

    def make_thumbnail(self):

        image = Image.open(self.photo)
        image.thumbnail(THUMB_SIZE, Image.ANTIALIAS)

        thumb_name, thumb_extension = os.path.splitext(self.photo.name)
        thumb_extension = thumb_extension.lower()

        thumb_filename = thumb_name + '_thumb' + thumb_extension

        if thumb_extension in ['.jpg', '.jpeg']:
            FTYPE = 'JPEG'
        elif thumb_extension == '.gif':
            FTYPE = 'GIF'
        elif thumb_extension == '.png':
            FTYPE = 'PNG'
        else:
            return False    # Unrecognized file type

        # Save thumbnail to in-memory file as StringIO
        temp_thumb = BytesIO()
        image.save(temp_thumb, FTYPE)
        temp_thumb.seek(0)

        # set save=False, otherwise it will run in an infinite loop
        self.thumbnail.save(thumb_filename, ContentFile(temp_thumb.read()), save=False)
        temp_thumb.close()

        return True

To do this, you should add a new ImageField to your 7 current UserImages model to hold the thumbnail, then 6 override your the save method to create and 5 save the thumbnail after the full image 4 is saved.

I've adapted the following snippet 3 of code from one of my projects that did 2 exactly this, I'm pretty sure this will 1 do exactly what you need it to do:

from cStringIO import StringIO
import os

from django.db import models
from django.core.files.base import ContentFile
from django.core.files.storage import default_storage as storage

from PIL import Image

# Thumbnail size tuple defined in an app-specific settings module - e.g. (400, 400)
from app.settings import THUMB_SIZE

class Photo(models.Model):
    """
    Photo model with automatically generated thumbnail.
    """
    photo = models.ImageField(upload_to='photos')
    thumbnail = models.ImageField(upload_to='thumbs', editable=False)

    def save(self, *args, **kwargs):
        """
        Make and save the thumbnail for the photo here.
        """
        super(Photo, self).save(*args, **kwargs)
        if not self.make_thumbnail():
            raise Exception('Could not create thumbnail - is the file type valid?')

    def make_thumbnail(self):
        """
        Create and save the thumbnail for the photo (simple resize with PIL).
        """
        fh = storage.open(self.photo.name, 'r')
        try:
            image = Image.open(fh)
        except:
            return False

        image.thumbnail(THUMB_SIZE, Image.ANTIALIAS)
        fh.close()

        # Path to save to, name, and extension
        thumb_name, thumb_extension = os.path.splitext(self.photo.name)
        thumb_extension = thumb_extension.lower()

        thumb_filename = thumb_name + '_thumb' + thumb_extension

        if thumb_extension in ['.jpg', '.jpeg']:
            FTYPE = 'JPEG'
        elif thumb_extension == '.gif':
            FTYPE = 'GIF'
        elif thumb_extension == '.png':
            FTYPE = 'PNG'
        else:
            return False    # Unrecognized file type

        # Save thumbnail to in-memory file as StringIO
        temp_thumb = StringIO()
        image.save(temp_thumb, FTYPE)
        temp_thumb.seek(0)

        # Load a ContentFile into the thumbnail field so it gets saved
        self.thumbnail.save(thumb_filename, ContentFile(temp_thumb.read()), save=True)
        temp_thumb.close()

        return True

I wrote it based by ziiiro's answer. It 2 works fine with Django2.2.1. Need process 1 for save for path of image field.

models.py

from django.db import models
from my.images import make_thumbnail


class Image(models.Model):
    image = models.ImageField(upload_to='')
    thumbnail = models.ImageField(upload_to='', editable=False)
    icon = models.ImageField(upload_to='', editable=False)

    def save(self, *args, **kwargs):
        # save for image
        super(Image, self).save(*args, **kwargs)

        make_thumbnail(self.thumbnail, self.image, (200, 200), 'thumb')
        make_thumbnail(self.icon, self.image, (100, 100), 'icon')

        # save for thumbnail and icon
        super(Image, self).save(*args, **kwargs)

my.images.py

from django.core.files.base import ContentFile
import os.path
from PIL import Image
from io import BytesIO


def make_thumbnail(dst_image_field, src_image_field, size, name_suffix, sep='_'):
    """
    make thumbnail image and field from source image field

    @example
        thumbnail(self.thumbnail, self.image, (200, 200), 'thumb')
    """
    # create thumbnail image
    image = Image.open(src_image_field)
    image.thumbnail(size, Image.ANTIALIAS)

    # build file name for dst
    dst_path, dst_ext = os.path.splitext(src_image_field.name)
    dst_ext = dst_ext.lower()
    dst_fname = dst_path + sep + name_suffix + dst_ext

    # check extension
    if dst_ext in ['.jpg', '.jpeg']:
        filetype = 'JPEG'
    elif dst_ext == '.gif':
        filetype = 'GIF'
    elif dst_ext == '.png':
        filetype = 'PNG'
    else:
        raise RuntimeError('unrecognized file type of "%s"' % dst_ext)

    # Save thumbnail to in-memory file as StringIO
    dst_bytes = BytesIO()
    image.save(dst_bytes, filetype)
    dst_bytes.seek(0)

    # set save=False, otherwise it will run in an infinite loop
    dst_image_field.save(dst_fname, ContentFile(dst_bytes.read()), save=False)
    dst_bytes.close()

If you don't want to implement a solution 2 from scratch I suggest you to use a django 1 app called sorl-thumbnail

Probably you have forgotten save a file:

im.save(file + ".thumbnail", "JPEG")

See 1 http://effbot.org/imagingbook/image.htm#examples

there is super easier way,

in model:

def upload_thumb_dir(self, filename):
        path = f'path_to_thumb.jpg'
        return path

thumb = ProcessedImageField(upload_to=upload_thumb_dir,
    processors=[ResizeToFill(192, 108)],
    max_length= 255,
    format='JPEG',
    default='preview.jpg',
    options={'quality': 80},
    null=True, blank=True
)
# ...
def save(self, *args, **kwargs):
    self.thumb = self.rawfile.file
    super(VersionPreviews, self).save(*args, **kwargs)

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