First, go to
www.photobucket.com and join. It's free of charge. You'll then choose the Upload option. You can upload photographs from your computer onto the photobucket website. Once you have them uploaded, you'll see that each picture has three links below it. You'll need to highlight the third/bottom link under the picture. Then copy it. Go back to these boards and go to the thread you want to post the picture to and click Reply. Then paste your photobucket link. Once it has been pasted, click Submit Reply. You're picture should be posted!
I am very computer illiterate and I was able to figure out how to post photographs to these boards.