django-photoprocessor

Step 1

$ pip install django-photoprocessor

(or clone the source and put the photoprocessor module on your path)

Step 2

Add ImageWithProcessorField to your models.

# myapp/models.py

from django.db import models
from photoprocessor.fields import ImageWithProcessorsField

thumbnails = {'thumbnail':{'resize':{'width':100, 'height':100, 'crop':'center'}, 'quality':90},
              'display': {'resize':{'width':500, 'height':500, 'crop':'center'}, 'quality':90}}

class Photo(models.Model):
    name = models.CharField(max_length=100)
    original_image = ImageWithProcessorsField(upload_to='books', thumbnails=thumbnails)

Step 3

Access your thumbnails

photo = Photo(name='myphoto')
photo.original_image.save('myfile.jpg', myfileobj)
print photo.original_image['thumbnail'].url