We need to go for Lazy Loading
Significantly speed up image-heavy galleries and takes no time at all to enable.
Most of us are familiar with the Lazy Load. Lazy loading forces images to load only when they are “above the fold”. This is very useful and it boosts performance delaying loading of images in long web pages because images outside of viewport (visible part of web page) won’t be loaded until the user scrolls to them. Lazy Load has some cool options such as grid loading effects.