Instead of prefixing everything with {{ STATIC_URL }} in your templates, use the template tag {% static 'foo/bar/img' %} which will allow you to do asset time-stamping/versioning,

https://docs.djangoproject.com/en/dev/howto/static-files/#wi...

Edit: forgot to link to the versioning part in the docs: https://docs.djangoproject.com/en/dev/ref/contrib/staticfile...

Edit edit: ADMIN_MEDIA_PREFIX is also depreciated from 1.4 onwards: https://docs.djangoproject.com/en/1.4/releases/1.4/#django-c...