By Shad Super in Questions —

Which Image Optimization Techniques, Like Responsive Images and Next-Gen Formats, Are Best Suited for Improving LCP and CLS Scores?

Summary

To enhance the Largest Contentful Paint (LCP) and Cumulative Layout Shift (CLS) scores, it's crucial to optimize images using techniques like responsive images, next-gen formats, lazy loading, and image compression. These optimization methods ensure speedy load times and a smooth visual experience making sure users don't deal with jarring shifts during loading.

Responsive Images

Art Direction

Art direction in responsive web design involves serving different versions of an image based on the viewport size, resolution, or orientation, utilizing the <picture> and <source media> tags [Use Srcset To Automatically Choose The Right Image, 2020].

Resolution Switching

Resolution switching involves offering different resolution versions of an image using <img srcset> and <img sizes> attributes. This makes sure the browser picks the correct image based on device resolution and viewport size [Serve Responsive Images, 2021].

Next-Gen Formats

WebP and AVIF

Next-gen formats like WebP and AVIF offer superior compression and quality compared to PNG and JPEG. They significantly reduce the byte size of images resulting in faster load times [Use WebP Images, 2021] [AVIF has landed, 2020].

Lazy Loading

Native Lazy Loading

Native lazy loading delays loading of images until they're needed using the <img loading="lazy"> attribute. This method improves initial loading times as images outside the viewport are not loaded immediately [Browser-Level Image Lazy Loading, 2021].

Image Compression

Lossless and Lossy Compression

Image compression techniques, like lossless and lossy compression, reduce file sizes without (lossless) or with some quality degradation (lossy). Implementing image compression can improve LCP significantly [Optimize Image, 2021].

Conclusion

Applying responsive images, next-gen formats, lazy loading, and image compression techniques can improve both the LCP and CLS scores of a webpage. These diverse techniques aim to enhance load times and the visual experience, crucial to improving overall web performance and user experience.

References