UPDATED: New version of code
Here is a template tag that generates arbitrary sized thumbnails of static images on the fly if needed. It also checks if the original image is newer than the template, and updates the thumbnail if need be. It's partially based on some code from django snippets.
import os
import Image
from django import template
from django.conf import settings
register = template.Library()
@register.filter
def thumbnail(file, size):
width, height = size.split('x')
width = int(width)
height = int(height)
basename, format = file.rsplit('.', 1)
thumb = basename + '_' + size + '.' + format
thumb_filename = os.path.join(settings.MEDIA_ROOT, thumb)
thumb_url = os.path.join(settings.MEDIA_URL, thumb)
filename = os.path.join(settings.MEDIA_ROOT, file)
if os.path.exists(thumb_filename):
if os.path.getmtime(thumb_filename) < os.path.getmtime(filename):
create_new = True
os.unlink(thumb_filename)
else:
create_new = False
else:
create_new = True
if create_new:
image = Image.open(filename)
image.thumbnail([width, height], Image.ANTIALIAS)
image.save(thumb_filename, image.format)
return thumb_url
