v151, template.thumbnail, what is the intended use?

None of that functionality it implemented - it was intended that the background image thumbnail could be stored on the template at some later stage.

We are looking to screen capture the layout upon save and store it in a folder then linked to the correct layout number so we can display it on teh Displays page along with the player list to show the current layout on each player.

Did you have a plan on code style? We are looking at Javascript to do the capture on the client side, then save to a sub folder under img. There are a few ways to capture regions of teh screen so we can get class='layout' to capture but in all our test we don't capture the actual pictures or screen of the video (if video window).
We have had better results using the canvas tag but in our attempts to do so with the layout div box we have failed. Any ideas?

We can capture a Div as an image to a folder.

Next, how can we save that image when the Layout saves, correctly named as well?
Then using 'template.thumbnail', how can we link the correct image from the folder to the UI using the DB?