The thing with the artwork though is, HBO had to provide all the official images to Stern. Stern didn't just go take a couple images from Google Images. HBO's marketing/design department had to send them the high quality images to work with. So while HBO had to approve the final design, they also approved any images they sent to Stern to use in the artwork.
I don't watch the show, so I have no opinion of the characters. But there are a few levels of approval. This wasn't just Sterns fault.