Purpose of use
To illustrate an important painting that is the subject of critical review. The image allows the viewer to see what the a representation of the subject. Without it, the viewer is unable to picture the work of art, detrimentally affecting the viewers understanding.
Replaceable?
no
Other information
The image linked here is claimed to be used under fair use in Whaam! as:
This is the main image in Whaam!, which is an article that entirely consists of analysis, commentary and criticism of Whaam!.
The subject of the image is a historically significant artwork as one of the cornerstone works that the Pop art art movement was founded upon in North America.
The image is only being used for informational purposes to depict the most important art work in the article.
Its inclusion in the article adds significantly to the article because it exemplifies an important topic from this article.
copies made from it will be of very inferior quality to the original,
the image is only being used for the purpose of analysis or criticism,
there is no alternative, public domain or free-copyrighted replacement available.