I can see how some people would see this as rude, but in some ways it's like having a face to face conversation: if someone raises a topic that upsets you, you can either bean-dip them or ask them to change the subject, because this subject is upsetting you. Different people have different tolerances, so how do they know it upsets you, if you don't tell them?
They don't. However, how many times do they need to be reminded before we need to regard them as total boors?
In that case just defriend them rather than tell them what they can and can't post on their own wall.
I'm not suggesting that you 'tell' them what to post on their wall; it has been agreed - and I agree - that would be rude. My suggestion is that you ask, politely, that they remove you from those specific postings.
True, but it's sort of like divorcing your spouse because s/he keeps whistling through his/her teeth, rather than speaking up and saying, "You know, that really bothers me, and I would consider it a favour if you stopped doing that."
Twik, that's a great analogy. Yes, comparing it to a divorce is somewhat extreme, but it does make my point (probably better than I ever did!), thank you. The options that have been suggested here so far are: put up with it or defriend/hide the poster. They just seem rather extreme when there is a more moderate approach available.
My suggestion, which I'm still unsure if it's rude or not, is to simply ask that the poster removes you from those postings. Facebook makes it quite easy to set up, so it's a simple request - would it really hurt or be rude to ask? Fair enough, they may say no, but does that make it rude to ask in the first place? They may choose to ignore your request, in which case you have to block photos or defriend, but is it not worth asking first, especially if there is a chance that they don't realise that their posts are upsetting you?
She could have asked me to stop posting cat pictures. She could have asked me to exclude her from the list of people who see my cat photos. Neither is reasonable for me to do. I post almost all my picture from my phone and they just go automatically to my photos. I could block her from my photo albums, but she can do it herself just as easily if she wants to. I expect her to manage her phobia herself. As far as I know, she expects to as well.
Re. the bolded, really? I am genuinely curious. Why is it not reasonable for you to take a minute or two to change your posting settings so that your posts do not upset your friend? If I knew that posting photos of a certain subject caused upset to a facebook friend, I would be quite happy to alter my settings so that those photos didn't appear in their feed. I already have different custom groups set up on my account, so that I can post items and they will only appear on the feeds of my friends who are also interested in them. If your friend blocks your photos, she can't see any of your photos, whether they are of your cats or of anything else that you've put up. Alternatively, if you take a minute or two to customise your postings (and you can set up groups so that it's a minute or two when you set it up, then you just choose that specific group when you post, it's not a minute or two every time you post), your friend is included in all your other postings and doesn't have to miss out.