I really don't think the image itself is the issue. It's the culture that would lead to brazenly sharing a porn magazine aroundnthe office, and subsequently using the image for a test photo. Then that same culture decided it should be standard because they liked looking at it. It indicates a culture of objectification of women. If an industry feels like sharing porn around is perfectly acceptable, you have to consider what else they think is acceptable. That's what makes people uncomfortable (I assume, though I'm a straight man so not personal experience, just empathy).