You can use a 3rd party program and a protocol called WebDAV to access your Resources folders or Drop Box folders for any given WISE site. This method will give you a drag-and-drop interface to your WISE files and also allow you to upload files that exceed the 50 Mb file upload size limit.
WITS currently recommends the program Cyberduck. It's free (donation based) and very easy to use. Other programs (such as Filezilla) will also work for WebDAV.