Django Error (13, 'Permission denied')

I am working on this photo device and sharing part of the application I am at http://lightbird.net/dbe/photo.html . I try to create a sketch and when I do it. I get this error.

I have Windows Vista.

  IOError at /admin/photo/image/add/
  (13, 'Permission denied')
  Request Method:   POST
  Request URL:  http://127.0.0.1:8000/admin/photo/image/add/
  Django Version:   1.4.3
  Exception Type:   IOError
  Exception Value:  (13, 'Permission denied')

  Exception Location:C:\Python26\lib\site-packages\PIL\Image.py in save, line 1399
  Python Executable:C:\Python26\python.exe
  Python Version:   2.6.0
  Python Path:  

  ['C:\\djcode\\mysite',
  'C:\\Python26\\python26.zip',
  'C:\\Python26\\DLLs',
  'C:\\Python26\\lib',
  'C:\\Python26\\lib\\plat-win',
  'C:\\Python26\\lib\\lib-tk',
  'C:\\Python26',
  'C:\\Python26\\lib\\site-packages',
  'C:\\Python26\\lib\\site-packages\\PIL']

  Server time: Sun, 10 Feb 2013 23:49:34 +1100

My models.py-

from django.db import models
from django.contrib.auth.models import User
from django.contrib import admin
from string import join
from django.core.files import File
from os.path import join as pjoin
from tempfile import *

import os
from PIL import Image as PImage
from mysite.settings import MEDIA_ROOT


class Album(models.Model):
    title = models.CharField(max_length=60)
    public = models.BooleanField(default=False)
    def __unicode__(self):
        return self.title

class Tag(models.Model):
    tag = models.CharField(max_length=50)
    def __unicode__(self):
        return self.tag

class Image(models.Model):
    title = models.CharField(max_length=60, blank=True, null=True)
    image = models.FileField(upload_to="images/")
    tags = models.ManyToManyField(Tag, blank=True)
    albums = models.ManyToManyField(Album, blank=True)
    created = models.DateTimeField(auto_now_add=True)
    rating = models.IntegerField(default=50)
    width = models.IntegerField(blank=True, null=True)
    height = models.IntegerField(blank=True, null=True)
    user = models.ForeignKey(User, null=True, blank=True)
    thumbnail2 = models.ImageField(upload_to="images/", blank=True, null=True)

    def __unicode__(self):
        return self.image.name
    def save(self, *args, **kwargs):
        """Save image dimensions."""
        super(Image, self).save(*args, **kwargs)
        im = PImage.open(pjoin(MEDIA_ROOT, self.image.name))
        self.width, self.height = im.size

        # large thumbnail
        fn, ext = os.path.splitext(self.image.name)
        im.thumbnail((128,128), PImage.ANTIALIAS)
        thumb_fn = fn + "-thumb2" + ext
        tf2 = NamedTemporaryFile()
        im.save(tf2.name, "JPEG")
        self.thumbnail2.save(thumb_fn, File(open(tf2.name)), save=False)
        tf2.close()

        # small thumbnail
        im.thumbnail((40,40), PImage.ANTIALIAS)
        thumb_fn = fn + "-thumb" + ext
        tf = NamedTemporaryFile()
        im.save(tf.name, "JPEG")
        self.thumbnail.save(thumb_fn, File(open(tf.name)), save=False)
        tf.close()

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

    def size(self):
        """Image size."""
        return "%s x %s" % (self.width, self.height)

    def __unicode__(self):
        return self.image.name

    def tags_(self):
        lst = [x[1] for x in self.tags.values_list()]
        return str(join(lst, ', '))

    def albums_(self):
        lst = [x[1] for x in self.albums.values_list()]
        return str(join(lst, ', '))

    def thumbnail(self):
        return """<a href="/media/%s"><img border="0" alt="" src="/media/%s" height="40" /></a>""" % (
                                                                (self.image.name, self.image.name))
    thumbnail.allow_tags = True
class AlbumAdmin(admin.ModelAdmin):
    search_fields = ["title"]
    list_display = ["title"]

class TagAdmin(admin.ModelAdmin):
    list_display = ["tag"]

class ImageAdmin(admin.ModelAdmin):
    search_fields = ["title"]
    list_display = ["__unicode__", "title", "user", "rating", "size", "tags_", "albums_","thumbnail", "created"]
    list_filter = ["tags", "albums"]
def save_model(self, request, obj, form, change):
    obj.user = request.user
    obj.save()

The problem is here:

from django.core.files import File
from os.path import join as pjoin
from tempfile import *

class Image(models.Model):
    # ...

    thumbnail2 = models.ImageField(upload_to="images/", blank=True, null=True)

def save(self, *args, **kwargs):
    """Save image dimensions."""
    super(Image, self).save(*args, **kwargs)
    im = PImage.open(pjoin(MEDIA_ROOT, self.image.name))
    self.width, self.height = im.size

    # large thumbnail
    fn, ext = os.path.splitext(self.image.name)
    im.thumbnail((128,128), PImage.ANTIALIAS)
    thumb_fn = fn + "-thumb2" + ext
    tf2 = NamedTemporaryFile()
    im.save(tf2.name, "JPEG")
    self.thumbnail2.save(thumb_fn, File(open(tf2.name)), save=False)
    tf2.close()

    # small thumbnail
    im.thumbnail((40,40), PImage.ANTIALIAS)
    thumb_fn = fn + "-thumb" + ext
    tf = NamedTemporaryFile()
    im.save(tf.name, "JPEG")
    self.thumbnail.save(thumb_fn, File(open(tf.name)), save=False)
    tf.close()

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

How to fix this error?