IPhone 6s display not crisp?

Finally did the upgrade from iPhone 5 to iPhone 6s today. All is great except I have noticed that for some reason, the screen on my 6s seems to display pictures (like on Instagram for example) slightly more blurry and pixelated than on my iPhone 5, which is weird because you'd obviously think it'd be the other way around. Not talking about pictures taken with the camera, I'm talking about the actual display performance when I'm viewing a web page or anything with images. The text displays fine as far as I know though. Anyone know anything about the display specs of this phone and why I could be experiencing this? I definitely am noticing quite a difference between the two.