property Thumbnail.Padding as String
Generates space around thumbnail. Clears the area around the content (inside the border) of the thumbnail.

TypeDescription
String A String expression that specifies the padding to left, top, right and bottom margins
By default, the Borders property is "0 0 0 18". Use the Alignment property to specify the caption being displayed on the thumbnail control. Use the Transparency property to specify the percent of transparency being used to paint the caption on the thumbnail. Use the Appearance property to specify whether the thumbnail displays a border.

You can use the following properties to define the distance and padding of the thumbnails