An artist paints a woman looking at the sky and smiling to symbolize freedom. what kind of appeal has the artist used?

The artist is using the appeal of pathos (emotional response). They play on the viewers association of the sky with endlessness, as it is often described as such. Additionally, most people associate the sky with birds which are used as mascots which hold value for freedom, like America's bald eagle. Lastly, people have an involuntary reaction to positive stimulus by smiling.

Pathos