You’ll need two windows open. First open up an “ADD NEW POST” window and then open up the image you wish to add listings to. Click “Edit” to edit the image.
In the New Post dialogue follow these instructions to generate the code to add new posts. Try to make the listings as specific as possible. Here’s how to do that.
That should generate a code that looks like this:
[idx-listings linkid="50233"]
Copy that code (including the brackets) into the image description. Save your image using the “Update Media” button. Then view the image attachement page. It should look something like this.
Open up a new window to generate the code. But don’t publish that new post. Just copy the code over here. Then “UPDATE” your image and look at the results.