Dynamically change storage location for Django's FileField and ImageField.

MyModel.py

from django.core.files.storage import FileSystemStorage

def MyModel(models.Model):
    # ... model stuff ...

    some_file = models.FileField(
        storage=FileSystemStorage(
            location='/my/private/path/'
        ),
        upload_to='downloads'
    )
    # files will be at /my/private/path/downloads/