Using the Storage Feature vs placing images in public/img

I have some thumbnails and I don't know whether to place them public/img or use Laravel's storage API. I'm going to be using the Storage File system anyways to upload the thumbnails, but what should i do about displaying them? Should I write a function in the Model that copies the photo to public/img when it's needed? Should I not worry about having thousands of photos in public/img?

I'm going to be using it as a css background image for a div so I'm just thinking of the best way to do this.

What's the advantage of storing the images through the Storage Api vs just storing them in public? Is it an issue of privacy/securing them from consistently sitting in public? Is there a performance reason?