If you open up the first post and then open up a picture from there, you can open them. It's probably to prevent people linking to their prictures directly, without including the site.
That's kinda strange. I had it posted as an image the first day the link was posted here and it worked fine. Now it shows as a red X. I also linked certain ones to IRC and the links worked then too, but now they don't...
I have to copy each link and put it into the address bar for it to work. Strange.
That being said, I think the Adventure one (http://www.llbbl.com/data/RPG-motivational/Adventure.jpg) is my favorite... Simply because I looked at it before reading it, and said to myself, "Hey, that's the Temple of Elemental Evil." Yeah, farming sounds good about now.
It's apache. You can disable linking to images from outside sites. If you simply copy paste it into a new browser it won't show up as redirected from SOD to that picture, thus it will work. You can also link it through some of the anon websites and it should work too.