Bartok can preview files like..

This is a test for Bartok UI system. If the image shows below, then a file at ./examples/image/image.png exists in the Bartok Client File System and is being delivered by a Service Worker.

If the Bartok Service Worker is not in place to handle these requests, then a grey box will show "MISSING IMAGE"

Below, the first image should be visible and the last image should be missing.