Its very easy!
The picture has to exist somewhere on the internet for you to show it here-it will not work from pictures directly on your hard-drive.
First off-get the full URL of the picture you want to post. The will be something like
When you create a post and want to insert the picture, simply put in this exactly as seen-yes even with those arrows on either end:
That's all there is to it! I have turned off the HTML for this topic so I could show you the code-it won't work here in the FAQ section. Copy the above line and go test it out for yourself in the "For Testing the Board Forum".