I think that the Brushstrokes series article should be merged into the Roy Lichtenstein article. I think as a general rule images of sources should not be included in articles on Pop art paintings. We don't find source material for James Rosenquist, Jim Dine, Tom Wesselmann or Andy Warhol in articles about them or their work. I don't see sufficient justification for the inclusion of images from advertising, comic books, or product packaging in such articles.