ASP。Net MVC存储在资源或内容中

I have a very huge amount of images (about 20K) that I don't want to be directly accessible by a user. Therefore I have a controller that streams a requested images back if the requesttoken is valid. I wonder now if I should store the images within a internal Resourcefile or just as content? I tried content before but you are able to access them from the browser if you know the folder and filename. The files don't change at runtime.I have a very huge amount of images (about 20K)