Again, watch the images as they load. The larger pictures take a lot longer to load, don't they?
That's because now the images are on the web, and you have to download them on to your computer. Even with a fast connection, the larger images take noticably longer.
However, notice that if you reload the page, the images probably load much more quickly. That is because your browser keeps a copy of files (pages and images) that it downloaded recently, so it can display the page again more quickly. This is called the browser cache.
You can go back to the page on your computer.