The "Image" tile displays the image assigned to the tile's "Background" setting.
It reveals the tile "Title" and tile "Content" when hovering over the tile similar to the SharePoint Promoted Links.
The tile can optionally be linked via the tile's "URL" setting.

Example: This example displays an image from the"Pictures" Sharepoint picture library. The tile also displays the tile "Title" and "Content" (if present). Title:IT Document Library Content:Cras mauris purus, tincidunt quis facilisis dapibus, cursus eu risus. Lorem ipsum dolor sit amet Background:http://somedomain/Pictures/somePicture.jpg