Minus

Minus is a free file sharing service and supports all file types (pictures, documents, music, videos, etc). Once you create an account, drag and drop files from your desktop and folders directly to your browser to share the files. There are also desktop and mobile apps to use and a Chrome extension and web app.  There is a maximum file size of 25MB and you can only put 50 items in a gallery (folder). But, there is no limit to the number of galleries you can create.  There is even a way to share files as a guest without an account which could be useful for students who want to share a file with a teacher. 
Thanks to Jonathon Wylie and David Andrade for posting on this service.