Simple but effective. Thanks!

Very basic redirection. It works, but it will try to forward every IG address including subdomains to ImgInn even though ImgInn only mirrors user pages. It does not seem to allow setting exceptions (as necessary for private pages or those that took down the ImgInn page) or skipping the redirect on demand. If you need to return to the original site for any reason, you will have to disable the extension and then re-enable it after.

Edit for dev's information request: To my knowledge, ImgInn only has an interface for user content so all other subdomains (i.e. not www) would not be a valid redirect. An example of which is help.* for the site's help pages.