The path will conflict with the {KoobooRoot}/Images folder, If you really want to do it, please create a custom HttpHandler to process the request.

Please go to see the routes.config, there are many custom routes in the files. You can create a new custom route before "{*PageUrl}" setting, then you can create a specify controller to handler your route request.

Alternative, you can create a page in the site to handler the image request via the page plugin. It is also a good solution for you.