The modern J.B. Harold character designs were finalized when the first two games got ported to Windows around 1995 and althi, the current rights holder, just kept using them for each subsequent release including the latest ports for Android/iOS/Switch.
I'm assuming here they may have wanted to include a port of an older version as a bonus feature before scrapping the idea. Or perhaps this was meant to be a part of a gallery showcasing the history of the game?
The modern releases are also a bit censored with certain elements like smoking and drinking at the bar missing depending on what version you play.

This might be more familiar if you played the TurboGrafx/PC Engine version (the most well known English version) because those are the same character designs. I think judging by the palette that this came from either the Sharp X68000 or the FM Towns versions.

Think the developers were starting out porting but then decided to completely change the look making them more Japanese in design (kind of reverting back to the original PC-88/98 of spriting rather than photos). The new designs were later used for the Switch and mobile releases.

Also laughs at the developers leaving the cursor on one of the pictures!