Online article from the Texas A&M Writing Center that discusses things to consider when writing about images.
"Visual images, including cartoons, book covers, ads, charts, graphs, photographs, and business logos, aren’t just pretty to look at. They communicate, just as words do. Sometimes they communicate with words, and other times they replace words entirely. You can analyze and evaluate how visual images..." https://writingcenter.tamu.edu/Students/Writing-Speaking-Guides/Alphabetical-List-of-Guides/Academic-Writing/Analysis/Analyzing-Visual-Images