While I agree with this statement in general and in OP's case, there are a few types of photos I think are unacceptable to display in public, or even on your personal device if you are in public where other people can see. I think we can all agree pornography is one, and the other type that gets me really upset is photos of animal abuse. There are some former veterinary colleagues where I've had to block their Facebook posts because they think it's OK to post graphic photos of abused animals, covered in blood and open wounds 😢 But photos of a swimsuit model aren't pornographic, nor do they depict graphic violence. I completely agree that OP's cow-workers were out of line.