Find out if a image, css, js file is used or not?

When I have a bunch of files in the Design pane, how can I find out if the file is used in my project or not?

You know, once quite some time ago I had suggested something on the order of the ability to see if Classes and ID's were actually in use, but you've hit on the other part of this with supporting files being in use or not. I too would like to know if there's a way we can add something to tell these things, without having to rely on external 3rd party apps and sites to clean our CSS or without having to go through every single HTML page to check for a Class/ID.

Right now though Robert, there is no way to see this without checking your pages, and unfortunately for those of us that may have very large numbers of HTML pages, this can be quite a daunting task indeed.

Would love it if mousing over an image (and later a CSS and JS file if the ability to set them for specific pages happens) and see a list of the pages that they are used in, or better yet an Information choice on the right click menu that would show us those things.

Robert, feel free to post a suggestion and use my suggestions here and/or reference this post. :)