Abstract: Provided is a file storing-and-managing method and device, for receiving, storing and managing electronic files over the Internet, the method and device including an effective and easy-to-operate GUI which can be operated visually and intuitionally without causing any stress. The file-managing device sends a graphical operation page to a user-computer connected over the Internet. The operation page includes a description (5) of the structure showing how the received-files are stored in the file-managing device and a description (7) of the structure showing how local files are stored in the user-computer, so that a user can easily upload and download files through graphical and intuitional operations of this page. Further, the file-managing device creates preview image data which is provided for previewing of the received-file and which has a data-size smaller than the original received-file. This preview image data is associated to and managed with the original received-file.