Django / PIL - save thumbnail version right when image is uploaded

Question

This is my forms.py:

class UploadImageForm(forms.ModelForm):
    class Meta:
        model = UserImages
        fields = [\'photo\']

and this i

Answer 1

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

Answer 2

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)

Answer 3

I wrote it based by ziiiro's answer. It works fine with Django2.2.1. Need process 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()

Answer 4

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

I've adapted the following snippet of code from one of my projects that did exactly this, I'm pretty sure this will 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

Answer 5

Probably you have forgotten save a file:

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

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

Answer 6

Based on xjtian's answer. This works for 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