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

django, image, python-imaging-library, thumbnails

Solution

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

Problem

This is my forms.py: ``` class UploadImageForm(forms.ModelForm): class Meta: model = UserImages fields = ['photo'] ``` and this is my models.py: ``` class UserImages(models.Model): user = models.ForeignKey(User) photo = models.ImageField(upload_to=get_file_path) ``` and this is my view: ``` def uploadImageView(request): if request.method == 'POST': form = UploadImageForm(request.POST, request.FILES) if form.is_valid(): instance = form.save(commit=False) instance.user = request.user instance.save() return redirect('/') else: form = UploadImageForm() return render(request, 'uploadImagePage.html', {'uploadImageForm': form}) ``` But this only saves the image being uploaded. How do I save a thumbnail version of the image as well with the thumbnail version of the image having the exact same name except with the word 'thumbail' after it? The tutorials I read said I can do ``` im = Image.open(infile) im.thumbnail(size, Image.ANTIALIAS) ``` to get a thumbnail but in my situation, the image isn't even saved yet.

Original source