WHAT IT'S USED FOR:
The Thumbnail URL is where your Web Server will look for the thumbnail images you include in the export. You should enter an address in this field for the thumbnails if you want the thumbnail images to be served by your Web Server. If you leave this field blank, the thumbnails will be served by the Application Server, which takes care of the dynamic content.
WHERE TO FIND IT:
The Images page of the Vernon Browser Advanced Configuration window.
HOW TO USE IT:
The Thumbnail URL you enter should follow the format: http://www.YourWebServer/images.
