Your comment "This article tells you how to... replace their posters with photos." is a little misleading.
This is what that article actually says:
"Contact posters belonging to other users cannot be deleted or disabled."
"...you cannot set up a contact poster for your contacts—each iPhone user is in control of their contact poster."
"Contact posters cannot be officially disabled."
Even the article's content is a little misleading. Where it says:
You can delete individual contact posters from your contact poster list.
Start by opening your Contacts app and selecting your card at the top of the list.
- Tap Contact Photo & Poster, then tap the Edit button in the middle of the screen.
- Scroll to the poster you want to delete, then swipe up on the poster. Tap the red trash can button to delete the poster.
YOU CANNOT DELETE INDIVIDUAL CONTACT POSTERS FROM YOUR CONTACT POSTER LIST. If you read this part carefully, it shows you how to delete YOUR contact posters when you selected YOUR card from the list. But if you disabled the Contact Poster for YOUR card from showing up on other people's phones and you follow these instructions to swipe up and delete your posters, you also screwed up YOUR PHOTO! Then you'll have to go back and add back Your photo to get it back.
Now, there is a section of this article that does talk about "However, there is a workaround to disabling another contact's contact poster", which I have already stated before in this thread. The only workaround that I have found was to Delete the Contact and re-create the Contact again and update their photo with something that I select. I normally try to do this from my PC using the iCloud app because the Contact Poster functionality has not been activated there (yet) and it appears that once the new Contact is created that there won't be a Poster for that Contact - just yet. But I haven't discovered, yet, if someone calls me and they have their Contact Poster setup for themselves, if it will show up on my phone. I believe most of my contacts know how I feel about this feature and maybe they've disabled it on their side. Only time will tell...
I did find something that was a little quirky about the Photos on the Contacts. It appears to depend on the SIZE of the photo that you select for the contact as to whether the photo will show up in a small circle or large circle when you view the Contact in your phone app. I had some contacts where the photo was small, and some were large. After editing the photo that I was going to use for the contact (using the Paint app on my PC) and making the picture larger and then selecting it for that contact and resizing it to make it appear as I wanted, they are all now showing up in larger circles consistently.
I thought about getting my wife to setup a Contact Poster for herself and then call me to see if it displays on my phone - without my permission. But I haven't yet wanted to go to that effort since she'll probably have to delete her contact and re-create it to get rid of the Poster. I know she could disable the Contact Poster sharing but I'm not sure what her own contact would look like on her phone until she re-creates her Contact info again, and I'm just not in the mood to go through that hassle.
And before "you-know-who" adds his two-cents worth, we're still looking for WORKAROUNDS. Yes, yes, yes we know the "Apple does not read this forum" rhetoric, so there's no need to post that link again.