Add multiple files to Media Library

You know how when you want to add an image to your page and you’re taken to the pop-up that let’s you add from your computer, from a url, from the gallery, or media library? Well, is there a way to load a bunch of photos in the media library or gallery? Maybe through FTP or something? I tried a while back, by locating a folder where some photos were, I dragged some more photos into that folder but when I was back to editing my my page, those photos did not appear in the media library.

I’m sure this has been asked, but haven’t found it in my search.

Thanks in advance.