"Billy", let me first say WELCOME TO THE BOARDS!
And thanks for your insights, particularly on whether it really was Hank Ketchum doing the covers. As to your question, there are 2 ways to do this.
The easiest way is if you indeed have your scans stored on another website, in which case you only need to click the "image" link below and then paste in the URL in the box that appears. This is the best method if you have really large scans.
The second easiest way is to use these boards as your website, but the size of your scan is limited to 150kbs. The steps are:
1. Post the text that you want to post, then hit "continue".
2. You'll see a prompt asking if you want to attach a file. Go ahead and attach the file, and then hit "OK, Submit".
3. You'll now be returned to the thread, and your post will appear at the bottom of the thread. You'll see a link to "attachment" at the top of your post. Click the link, and you'll come to a page with your scan. Copy the URL for that page, then return back to your post.
4. Click the edit link for your post. Now click on the "image" link, and then paste in the URL for your scan into the dialogue box that pops up.
5. Confirm you want to make the change, and you should get a test page showing what your post will look like, including the scan. Click continue and voila, back in the thread with your scan now showing.