I have this theory; seeing as how people generally go to the doctor when they are already feeling sick possibly having posters of gross stuff on the walls is not a good idea. Unless there are extra buckets around.
I have been unwell this last week and ended up having to go to a doctor that I haven't been to before. After sitting down I closed my eyes for a moment the looked up and was greeted by the sight of a severely infected toe. Ewwww, gross.
It reminded me of the hospital in Vanuatu, all around the waiting room were pictures of different forms of leprosy. To a 10 year old it was always morbidly fascinating. Now I think it would just make me heave.