The exhibition Star Wars: Identities is currently in Montreal. Although I have not seen it yet, I was quite impressed with the artwork for the posters used to promote the exhibition. Here are a couple of the posters that I was able to find online. Pay close attention to the details in the picture. Each one reveals extra details once you look deeper. You can download any of these posters as desktop wallpapers. Their resolution is pretty good.
You can learn more about the Star Wars: Identities exhibition by visiting http://www.starwarsidentities.com
Its a fantastic exhibit. I saw it in Vancouver and absolutely loved it