What's wrong about looking at some pictures that are by no standards NSFW? And again, at work you're supposed to be working, not checking out the latest js libraries and commenting on HN, so the fact that the pictures are those of Emma Watson or those of Peter Pan is irrelevant.
I do web dev work in an open office area where I'm surrounded by people who don't really understand what I get paid to do.
My boss is aware however, and I'm very confident that me investigating new js image viewer libs, browsing and posting on HN falls with in my job description.
I instantly closed the demo gallery because as much as it annoys me the perception of those around me matters.
I'm completely on board with your thoughts that these images are SFW and it shouldn't be an issue. I'm confident that I would be able to rationally explain why I happen to have a page full of Emma Watson pictures open. However, I wouldn't get the chance to explain. If someone around me noticed they'd immediately think that I was slacking off and looking at pictures of cute women on the internet.
If the demo images were of basically any other SFW subject matter it wouldn't be an issue.
I totally agree that the whole situation that this is even a concern is annoying as all hell. That doesn't stop it from being a thing.
At this point I'm not sure if it's even the perception of those around you and not what those around you think the perceptions of those around them might be.
