Restricting /assets to non logged in users

@Omar Crespo: I can't see how that would work for images and files. You can't just say process it as normal if you have asked PHP to handle it.

Usually, you have the images posted on a view, so, if the user isn't loged in, then he will be redirected to the login page.

You won't be restricting the images, you'll be restricting the view that holds the images. After all, only loged users should access to the private pages of your website.