Find a website to host your picture. Upload the picture to the website that would host you pictures. Copy the link where the pictue is hosted. (i personally use geocities.com to host my picture.) And whenever you want to post a picture just go the "image button" that's right below the message box of reply or new thread. Click on the "image" button and paste the link of the picture. Hope it helps.
You have the wrong link. If you want to get the link to your image. Go to the page and right click on the image and click on property. There's a http address for that specific image. Copy that http address and tried it again. You shouldn't have any problem.