I am using Poster Stack for blogging on my website. At post no.3 and no.4 the images are not showing/loading on the main page. I use Impact for a slideshow, which works fine on the first two postings.
I see the preview images on the main page but if I click on post 3, I am not able to see the Impact images (though it does seem to be making space for it).
As @teefers says, there are some errors on the page which may be interfering with things, though i don’t know how to troubleshoot them specifically.
You also have a couple of massive image files on that post 3. Both almost 4MB’s each. It may not fix the problem but you should definitely resize and optimize your images.