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 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.

Answer 1

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