Styling Thumbnail Shapes when Rendering from Geometry
When you choose to Render Thumbnails from Geometry, you can also choose to style the rendered shapes themselves. To apply Styles to the rendered shapes:
In the Manage > Discovery > Locations, select the Thumbnails tab
From the dropdown, select Render Images from Geometry
Check the box next to Style rendered shapes
From the Shape Type drop-down menu, choose Point, Line or Polygon (you can then further select MultiPoint, MultiLine or MultiPolygon from the Shape Type drop-down menu)
Adjust the settings in the Style box
stroke-color and fill-color use standard hex values as input
stroke-width sets the width of the line or polygon - enter 0 for no line
fill-opacity and stroke-opacity control how transparent the shape is on a scale of 0 to 1, where 0 is transparent and 1 is completely opaque
For Points, you can adjust shape (circle or square), fill-color and fill-opacity
For Lines, you can adjust stroke-color, stroke-width and stroke-opacity
For Polygons, adjust stroke-color, stroke-width, fill-color and fill-opacity
Click Preview to see those settings in the Preview box
Click Save when you are done