Final answer:
John Neagle contributed to early American art through his skilled portraiture, capturing the character and personality of individuals, which was a significant element of the American Realism movement.
Step-by-step explanation:
John Neagle was an influential artist in early American art, best known for his remarkable portraiture. Unlike some of his contemporaries who were inspired by the American landscape, Neagle made significant contributions by painting portraits of individuals that revealed their character and personality. His work captured the essence of American society and its people, offering a window into the life and times of early America. Neagle's portraits are valued for their vivid depiction of his subjects and are seen as a significant part of the American Realism movement, which focused on themes of democracy, the everyday life of people, and the spirit of the nation.