The following images are loaded sequentially in an attempt to load the visible images faster.
Open the timeline in the web-inspector to properly observe the result. You also might want to clear your caches to clearly see the result.
Original image: here
Original image: here
Original image: here
This page demonstrates how to make the images load as the user scrolls. Just scroll down, you'll see.
Original image: here
Original image: https://i.redd.it/d9tnox3a0x101.jpg
Original image: https://upload.wikimedia.org/wikipedia/commons/7/7d/Atomium_de_Bruxelles.jpg