The original image of the person on the boat at dusk is 1000 x 667 pixels, so I'm pretty sure they cropped that. It's also being displayed at 1500 pixels wide,

The original image of the person on the boat at dusk is 1000 x 667 pixels, so I'm pretty sure they cropped that. It's also being displayed at 1500 pixels wide, so it's being enlarged from the original. It's a Squarespace site, and I wouldn't mind betting that either Squarespace or the author did some compression on the photo before they uploaded it so the page wasn't slow to load too. I'm not sure there's much you can tell from the quality of that image.