I didn’t call it unambiguously NSFW. The top comment (not mine) didn’t either, they used the qualifier “semi”. This obviously isn’t porn, it’s art. The famous Lena image has no breasts at all, and it’s considered semi NSFW. https://en.m.wikipedia.org/wiki/Lenna “it is no longer considered appropriate by some authors” … “Suggestive pictures used in lectures on image processing ... convey the message that the lecturer caters to the males only.”

You don’t have to be in a puritanical setting for some women and men around you to be uncomfortable with your pin-ups, regardless of which body parts are visible. They might never even say anything about it, and yet it can still be slightly inappropriate and/or unprofessional.