The style looks like Peter Dennis's (90% certain). Prolific, talented and knowledgeable military artist works for Osprey and Warlord Games etc
Actually the illustration is on the Warlord Games Polish Vistula Legion box and of course contains a figure like the one referred to.
Seems strange to mention the illustration but not its creator which was of course not Mr Rospond who was the author.
You are correct. Peter Dennis is credited with the cover illustration on page 3 of the book. My reason for highlighting the book in general was as a recently released reference source.
The book itself contains many pictures from a variety of artists, some of these are well known (Knotel etc), others are new to me. e.g including Polish troops of the early legions, 114th Demi Brigade in 1802, or the Jewish National Guard of Warsaw. A very interesting read, and a good primer for anyone considering creating Polish forces and their evolution over the Napoleonic era.