Guess file extension based on content-type. When downloading a file, and no path is supplied to store it, guess the file extension using mimetypes and the content-type header. Also supply a unit test for the HotLinkImageForm.

from django.apps import AppConfig


class BioConfig(AppConfig):
    name = 'bio'
    verbose_name = 'Biography'

    def ready(self):
        import bio.receivers