Global Mapper v25.0

Stitch lines ... how to resolve?

I've added a series of tiles obtained from USGS.  However, it looks like they aren't stitched together in Global Mapper 20.1 

https://drive.google.com/open?id=1bz-JicpxofCrE9WbGPLlP9IY9d3wxj6X

Is there a stitching process I need to initiate in Global Mapper?

I need a single stitched image (aka no black lines).

Cheers, Rob.

Answers