I don’t know where they found that stock picture of the p-38 in flight, but that isn’t a standard model. Looks like experimental mods to the wings. The one in the sand has the standard wings.
It also has a longer center fuselage than normal. Judging by the streamlined engine nacelles It's a pre-J model P-38. I found this on Wikipedia:
One P-38E was fitted with an extended central nacelle to accommodate a tandem-seat cockpit with dual controls, and was later fitted with a laminar flow wing.