This is a great picture and it's easy to explain why. It's simply because Homer Simpson and Darth Vader are two of the most famous fictional characters ever. You can't go wrong with combining the two. This comes off as being like Darth Helmet. You know, a goofy Darth Vader parody? The artwork is just great.
It looks like he's wearing sunglasses. Well...different from the ones Vader usually has. Good thing he can drink beer like that. His crotch is really showing. It's just funny.