This sample explains you about the Dropdown Tree item that can be configured by the icons or images. Click on the icon or double click on it to expand or collapse and to show the icons or images that are configured with the items.
The Dropdown Tree control has the built-in option to customize each item's appearance with the icons and images by mapping the iconCss and imageUrl fields. In this demo, the Dropdown Tree is showcased like a file system with custom icons and images.