This section is specified for all your media-related images if any. For instance, when you have to display and upload any image related to any product or for any other purpose, you need to upload it first to the media gallery section using give link below.
In order to add more images or media files, click on the add new option and upload images in pop up window.
Click on the middle section and upload the files existing on your computer hard drive. Any file that you upload here would be readily available in your media section.