Lazy loading of images saves page rendering time and traffic for online photo albums. Usually one album has many images and to load all of them is time and traffic consuming. Therefore we are using Lazy Loading principle for our photo albums.
The visibility zone images will be loaded first. Plus, three images more are preloaded to predict user scrolling or viewing in the photo gallery. All other images will be loaded 'on demand' (after some person's actions): scrolling; opening the gallery and swiping the images.
All popular browsers are saved images in cache storage. It means the rendering of an album will be even faster next time when a person opens the same album.