Django LFS - regenerate image scales

import sys
from django.conf import settings
from django.core.management.base import BaseCommand
from django.core.files.base import ContentFile
from lfs.catalog.models import Image


class Command(BaseCommand):
    help = "Removes and recreates all scales for all LFS Images"
    args = ''

    def handle(self, *args, **options):

        if settings.MEDIA_ROOT == '':
            print "MEDIA_ROOT is not set, nothing to do"
            return

        progress = 0
        total = Image.objects.count()
        for img in Image.objects.all():
            filename = img.image.name.split('/')[-1]
            try:
                content = ContentFile(img.image.read())
            except IOError:
                print >>sys.stderr, "Invalid file:", img.pk, filename
                continue
            img.image.delete()  # remove all scales and files in media dir
            img.image.save(filename, content)
            del content
            del filename
            progress += 1
            if progress % 500 == 0:
                print >>sys.stderr, "Progress: %s/%s" % (progress, total)