At runtime, the user can resize the thumbnail, by click and drag the middle mouse button or by double-clicking the thumbnail. Excludes the exThumbnailAllowResize flag from the Mode property to disable resizing the thumbnails when the user click and drag the middle mouse button. Excludes the exThumbnailAutoFitOnDblClk flag from the Mode property to prevent enlarging the thumbnail when user double-clicks it. The exThumbnailKeepAspectRatio flag of the Mode property specifies whether the thumbnail is keeping its aspect ratio when it is displayed in the control. The exThumbnailStretch flag of the Mode property stretches the thumbnail on the frame's client area. 

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

• The Borders property indicates the margins where the thumbnail is displayed, relative to the control's border.
• The Margins property specifies the distance between thumbnails, when multiple thumbnails are displayed on the control.
• The Padding property generates space around thumbnail. Clears the area around the content (inside the border) of the thumbnail.

The following properties specifies the size of each thumbnail:

• The ThumbnailWidth property specifies the width to display the thumbnails.
• The ThumbnailHeight property specifies the height to display the thumbnails.

The following properties specifies the limit / range of the size for of each thumbnail:

• The ThumbnailMinWidth property specifies the minimum width to display the thumbnails.
• The ThumbnailMaxWidth property specifies the maximum width to display the thumbnails.
• The ThumbnailMinHeight property specifies the minimum height to display the thumbnails.
• The ThumbnailMaxHeight property specifies the maximum height to display the thumbnails.