I have a need to "attach" one image from the media library to each post. However, I can't discern how one does this. There is a feature in the post editor that allows me to "insert" an image into a post but it doesn't always "attach" it.
I uploaded about 50 images to media library, created the corresponding posts, then inserted the appropriate image into each post. Afterwards about half the images are shown as "attached" and half not, even though I did exactly the same thing on each one as far as I can tell. All the images show up in the post they belong with, even the ones that are indicated as not "attached".
I'd expect the image insertion dialog to have something like a checkbox indicating whether or not an inserted image should also be attached but I can't find anything like that. I've read docs and searched via google but can't find any clear explanation how to specify that I want to attach an image that I'm inserting into a post. Can anyone elighten me?
I'm aware I can retro-actively find and re-attach the missed ones through the media library but this is very tedious. I'd prefer to make sure 100% of them get attached when I insert them so it's just a single process for each post.