Loading all images in a slider at once can slow down your application, especially when working with large images or many slides. Lazy loading improves performance by loading images only when they are about to appear on screen.

In SwiperJS, lazy loading is handled using the browser's built-in image loading behavior. To enable it, you simply add the loading="lazy" attribute to images inside your slides. The browser will then delay loading each image until it is needed.

This approach reduces initial load time, lowers memory usage, and helps your slider feel faster and more responsive—especially on mobile devices or slower networks.

Here is an example of a SwiperJS slider in React with lazy-loaded images:

import { Swiper, SwiperSlide } from "swiper/react";
import "swiper/css/bundle";

function LazySwiper() {
  return (
    <Swiper spaceBetween={20} slidesPerView={1}>
      <SwiperSlide>
        <img
          src="https://picsum.photos/600/300?random=1"
          loading="lazy"
          alt="Slide 1"
          style={{ width: "100%", borderRadius: "12px" }}
        />
      </SwiperSlide>

      <SwiperSlide>
        <img
          src="https://picsum.photos/600/300?random=2"
          loading="lazy"
          alt="Slide 2"
          style={{ width: "100%", borderRadius: "12px" }}
        />
      </SwiperSlide>
    </Swiper>
  );
}