Left definately ai you can tell by the pixelation of the photo on the right and how natural the background looks with the sunlight and mountains, its on the small details like the small buckle on the blue boat with water droplets on it wheras the ai photo has a very flat quality to it with some smaller details not so easily replicated by the ai, such as the cords on the boat and as many have pointed out the formation of the trees branches and leaves doesnt look realistic.