Don, I'm not sure you *have* to post externally -- that's just what most people do.
You can attach the images to the post... you may not see the options in the fast reply window, but if you click 'More Reply Options' or are in the main posting page, you can do it. Here are the steps:
1. Start a post
2. At the bottom, click Choose file
3. Select the file to add and click OK
4. Click 'Attach this File'.
5. Once the file is attached, it will show up as an asset in the reply window. Click 'Add to Post'. An attachment link will be placed in line. You can copy/paste the link to the location you want the photo to show up. I'm adding mine below here:
6. Click Post!
It may not be intuitive or the best, but I've seen poorer interfaces too.