I read this guide about serving static media with Django during development.
I noticed that MEDIA_URL and MEDIA_ROOT were not used in this.
In a production situation you will want your media to be served from your front end web server (Apache, Nginx or the like) to avoid extra load on the Django/Python process. The MEDIA_URL and MEDIA_ROOT are usually used for this.
Running the built in Development server you will need to set the correct url in your url.py file - I normally use something like this:
from django.conf import settings
urlpatterns += patterns('',
(r'^media/(?P.*)$', 'django.views.static.serve', {'document_root': settings.MEDIA_ROOT}),
)
Which picks up the MEDIA_ROOT from your settings file meaning that it works for development and live.