Tim, I think that you're taking the Geek approach (and I'm a degreed Geek!).
What I'm going to do right now is go to a random gallery and display a picture. Then I'm going to right-click on the picture with my mouse and select
Copy from the menu that pops up.
Now, I'll return to this message and click my mouse just past this line to set the cursor position in this message.
Then I'll right-click again and select
Paste.
The picture then appears in my edit window.
If I go to
Preview Post, it is still there, so I just call it good and click
Submit Reply and I'm done.
Unless this is doing something ugly like actually embedding the message as opposed to providing a link that gets automatically expanded this seems like a simpler approach.
I make my living saying "ignore that Geek behind the curtains".