The first amendment does not apply to corporations/companies/businesses, especially customer-oriented businesses.
Read what you want at home, I would suggest not reading this at work--better to be safe than sorry. A coworker could feel 'harassed' by those pictures, a customer might be offended, and of course it could be argued that if your job is slow enough for you to peruse an artbook, is your job really necessary?
It's a necessary yet unintended consequence of the 'feel good' society we have created, where it doesn't matter if you're right or wrong, but how you 'feel'. Of course, the logical extension of that is that if anyone feels anything or expresses anything, *someone* is not going to like it. Rather than say, "Well, then we can't make 'feeling' the priority," the social powers that be have decreed, "Fine, then express nothing."
And in the customer perspective, it's not even about being sued--it's about losing or keeping customers [and thus making money]. How many random customers coming into a restaurant, say, would think, say, wearing a Dead Kennedys T-shirt about "Kill the Poor" would be appropriate/fitting? First impressions do count, and are a good way to lose a customer, possibly forever.
When we sold our house, in addition to the usual advice [good lighting, make space, un-clutter, nice smells, etc], the realtor told us to hide anything that was either too personal or possibly offensive--this could include anything from a political sticker, to a cross/star of David/pentagram symbol, to a Slayer poster, to porn movies, etc., otherwise run the risk of 'losing customers.'
