Set the MEDIA_ROOT and MEDIA_URL values.
These are fields django defaults to blank values.

MEDIA_ROOT: This is where Django stores uploaded files.
MEDIA_URL: This is where Django serves files from.

https://docs.djangoproject.com/en/1.6/ref/settings/#std:setting-MEDIA_ROOT
https://docs.djangoproject.com/en/1.6/ref/settings/#std:setting-MEDIA_URL