When scanning an image using the <Auto Size> auto-acquire feature, extra space is being returned around the image.
Dust and scratches on the scanner flat bed are being misinterpreted by the software as being part of the image.
Reduce the AutoDetect sensitivity factor:
Select TWAIN Devices ... from the Tools menu.
Double click on the TWAIN device returning the extra space around the image.
Set the Sensitivity to Normal Sensitivity.
Reduce the Sensitivity Factor to the next level (typically, this factor should be set to Medium).
Consult XVa3's on-line documentation for more information on scanning and acquiring images from scanners.