The add folder functionality allows you to create a structure into which you can upload images and other files so you can use them with your themes. This function is not available for all of the prepackaged themes.
To add a file to the root folder:
Navigate to Control Panel Dashboard > System Administration > Site Administration > Site Content > Site Files.
Click Create New Folder.
A Create New Folder dialog window displays.
Enter the folder name and click Save. The folder displays in the workspace.
You can upload a site file to the new folder by browsing to it and clicking Upload. To view the list of files in a folder, click the folder name.