Step 1:
Click "reply" to start a new post which should bring you to the message box below

Step 2: Click the "Insert Image" button on the left

Once you click that button it should automatically post the image code

Step 3: Upload your images to a website host such as
http://postimage.org http://tinypic.com and copy your image link. You will need to paste your code in the middle of the code with no spaces such as below

If your image is hosted somewhere and you did the image code correctly your image should appear like below once you post or preview your post.
