Me too. This is what made me flag it:

"I’m always flabbergasted how small—seemingly irrelevant—changes can make a big impact

If that was true, the author would have told us about those big impacts he witnessed. I think it's all made out of thin air.

If he just said "here is a couple of research papers that might be relevant to photos on websites" I would have no problem with the article. But they way it is presented, it's not HN worthy.

This is a topic I am very interested in. I studied many a/b tests on the impact of photos and other elements on conversion rations. The impact is usually surprisingly small.