ThumbnailsΒΆ
Thumbnails should automatically be generated. You can force the recreation of a thumbnail -from a resource Detail view, click on Edit Map/Layer. Click on Edit under Set Thumbnail in the popup window.
You may need to clear the browser cache for the new thumbnail to show. In Chrome, open the History window (Ctrl + H).
Click on Clear browsing data:
Select from the beginning of time and ensure Cache images and files is selected:
The updated thumbnail should now show: