This module exposes a function which can relativize URL's on a webpage.

This means that one can deploy the resulting site on http://example.com/, but also on http://example.com/some-folder/ without having to change anything (simply copy over the files).

To use it, you should use absolute URL's from the site root everywhere. For example, use

<img src="/images/lolcat.png" alt="Funny zomgroflcopter" />

in a blogpost. When running this through the relativize URL's module, this will result in (suppose your blogpost is located at /posts/foo.html:

<img src="../images/lolcat.png" alt="Funny zomgroflcopter" />