-------------------------
- Add a `delete` method to the Image class.
- Add a `replace_content` method to the Image class, which can be used to
modify the image.
- Fix URL for pyramid documentation.
- Use `tempfile.gettempdir()
<http://docs.python.org//library/tempfiletempfile.gettempdir>`_ to get the
temporary directory for tests instead of hardcoding ``/tmp/``.