Signal to resize uploaded Fiber images as new thumbnailed images

from os import path
from StringIO import StringIO
from PIL import Image as PILImage

from django.core.files.base import ContentFile
from django.db.models.signals import post_save
from django.dispatch import receiver

from fiber.models import Image


@receiver(post_save, sender=Image)
def resize_as_a_new_fiber_image(*args, **kwargs):
    im = kwargs.get("instance", None)
    max_width = 450
    max_height = 300
    if im.image.width > max_width or im.image.height > max_height:
        size =  (max_width, max_height)
        image = PILImage.open(im.image.path)
        xxx, image_name = path.split(im.image.path)
        if "." in image_name:
            image_name, extenstion = image_name.rsplit('.', 1)
            name = "%s_cropped.%s" % (image_name, extenstion)
        else:
            name = "%s_cropped" % image_name
        format = image.format
        if image.mode not in ("L", "RGB"):
            image = image.convert("RGB")
        resized_image = image.copy()
        resized_image.thumbnail(size, PILImage.ANTIALIAS)
        fp = StringIO()
        resized_image.save(fp, format, quality=128)
        cf = ContentFile(fp.getvalue())
        fiber_image = Image(title=im.title)
        fiber_image.image.save(name=name, content=cf, save=False)
        fiber_image.save()