Sure, we could make such a policy, but we already have a very strong policy prohibiting medical advice questions. It's so strong that it's spelled out in bold in the very first sentence of the disclaimer box on the site's main page, and also in bold again in the help section. And yet we close several such questions every single day. Some days it can be a half dozen or more. The problem is that people often land here from web searches, and they don't read anything before they ask, even if it's in bold text. So I give the odds of such a policy having any effect as close to zero.
Also, keep in mind that this is a medical forum, so it's entirely possible -- even likely -- that some people may encounter pictures they find objectionable even in perfectly valid questions. It would be nice if the OP used the hide feature, but I don't believe that should be enforced. You won't find such a policy in medical journals or college-level classrooms because sometimes medicine is just plain gross and it needs to be shown to be understood. That's the level of discourse we're trying to achieve here.
If a valid question contains a photo that some might find objectionable, the criteria I'll apply are: 1) Is it inappropriate to be seen by teens as young as 13? 2) Is it unnecessary to understand the question? 3) Is it overtly prurient? 4) Is it so emotionally disturbing that even medical professionals will recoil? If the answer is yes to any of those, I'll edit to hide the photo, redact the photo, or delete the question, whichever seems more appropriate.
But redacting something from a post requires at least one other mod to approve it, so it's not something that can happen instantly. It could easily take 24 hours or more, during which time you might see it. The only thing a mod can do that will be instant is deleting the question, and that's something we rarely do. There's a good reason for that: the OP needs to see why their question was rejected, and if we delete it they won't.
All that said, that was not a valid question and I closed it 3 minutes after it was posted. I understand that you can still see closed questions, but for the reasons explained above, there's not much we can do about that.