I'm curious about the different displays of pictures? Is this just trying out different styles or do they mean different types of information?
They denote different types of information. You can't really tell from that image, but the circles are actually people's forum (Discourse) avatars. Those posts get pulled to the homepage from the community. The square images are blog articles. I originally designed it with bars between each row indicating that (ie "Latest Community Discussions" "Latest from FeverBee" etc) but they got culled in an attempt to fit more posts on the homepage.