To add a picture to a thread click on the add reply button, then go to the bottom left under the smilies:
Click to view attachment Hit the browse button and find the pic you want to add on your computer and select "open". It takes you back to the thread and the name of the file is in the browse section. Select "add this attachment". Then the pic will be uploaded. You then have a couple more steps, which is to select "add this file to post" and then "add this" at the bottom. You can upload multiple pics before selecting "add this" if you want.