I don't think the images are a problem. Like the other commenter said i think it's the use of whitespace. The story feed seems quite narrow compared to hn. There's lots of deadspace to either side. I think you could increase the usage of space while not compromising on the images.

Please too, put the subscribe thing at the bottom of the page, not the middle. That just reminded me of a midpage banner add. It disrupted the reading flow very obviously.

It's a terrible spot for it.