Images processing apps

django-imagekit

from django.db import models
from imagekit.models import ImageSpec
from imagekit.processors import resize, Adjust

class Photo(models.Model):
    original_image = models.ImageField(upload_to='photos')
    thumbnail = ImageSpec([Adjust(contrast=1.2, sharpness=1.1),
            resize.Crop(50, 50)], image_field='original_image',
            format='JPEG', quality=90)