This is a simple plugin, it requires that you have multi-site install and properlly configured the WPMUDEV Multi-DB plugin that can be found at https://premium.wpmudev.org/project/multi-db/
The Wordpress Plugin WP ImageHost is a simple and easy to configurable plugin to host your images inside your blogposts on a separate subdomain to reduce the number of requests.
Changes the cookie default path to / (i.e. the whole domain.com not just domain.com/blog), and changes the domain to allow for sub-domains to use the cookie (www.domain.com to .domain.com)