You're getting two things confused.
You started a
thread in our
forums (your P&M blog) and you're looking at the tutorial for
articles. You haven't created an article, you've created a forum thread.
You're just using the wrong image code from the Dakka gallery page, you're using the ones for articles instead of the ones for forum posts.
See the Dakka
FAQ here and it should answer your question:
http://www.dakkadakka.com/dakkaforum/posts/list/0/205120.page#1030056