Asubha...our bodies are already Asubha. Do we need to see others' Asubha?
Asubha meditation is useful for some people who are crazy of Sensual Desire. But, not for everyone.
Asubha teaching can be dangerous for some people. According to some Sutta, some monks committed suicide after listening to Asubha teachings.
I got a book on Asubha and it says that only brave people dare to see Asubha pictures. Is this a True or Dare game? Some people find that seeing Asubha pictures is creating more suffering, does it mean that they are not brave enough to face life? I find it funny.
People who work in autopsy room, see Asubha everyday, but they still don't realize Dhamma. Why? It is not because the Asubha that able to cause people realize the Dhamma. But, the most important is our understanding in learning and practicing Dhamma.