Scroll down towards the bottom third of the article- that's where the posting tutorials are. Basically, you need to upload the image to a hosting site (suggestions for hosting sites listed in article) or upload the image to your RC gallery. The downside of using the RC gallery is the size limit. Anyhow, once you have the image uploaded you will copy the url [internet address] of the image and paste it into the box that pops up when you click on the IMG button. Don't hesitate to holler if you have more questions.
Greg