If you are using facebook to post your picks or link to them, you need to right click on the picture, click "view image" and copy that link to your post. Your picture will not show up in the thread, but people will be able to see that link.

Also, I always advise using an online site like photobucket or flicker, they are free and you can post your picture directly into the thread. If you only post links you will get much less people to look at your thread and respond, people don't like the extra work