Rendering Thumbnail images from Geometry
One of the strategies for generating Thumbnails involves rendering an image from the geometry or spatial information in indexed records.  Although this is generally the slowest method of generating thumbnails, it does offer some fine control over the styling of resultant shapes with the Style Rendered Shapes controls.  Rendering Thumbnails from Geometry can be very time-consuming - see this article for tips on speeding up the rendering process.
Enabling Thumbnail Rendering from Geometry
To enable rendering thumbnail images from geometry :
Go to Manage Voyager > Locations
Click the Edit icon next to a locationÂ
On the Thumbnail tab for that location, select Render Images from Geometry from the Strategypull-down menu
In the next dialog:
Â
Â
Choose a Base Map
Choose a Buffer value for the rendered image
Check Style rendered shapes to define how the shapes appear (described below)
Click Save when you are done