Implement Lazy Loading for Images

Improve performance by deferring offscreen images with native loading

Intersection Observer

Use loading="lazy" on non-critical images. Keep above-the-fold hero im

Placeholders & Blur-Up

live demo · related simulation● LIVE

Use low-quality placeholders (LQIP) or dominant color backgrounds to p

Intersection Observer Fallbacks

Frequently asked questions

What is Intersection Observer and how does it relate to lazy loading?

Intersection Observer is a browser API that detects when an element enters or exits the viewport. This allows you to trigger image loading only when the images are actually visible, significantly improving page load times.

Why is it important to include alt text for all images, even those loaded lazily?

Alt text provides a textual description of an image for users who cannot see it, and is crucial for accessibility. It also helps search engines understand the content of your images.

How can I test lazy loading performance on different network conditions?

Throttling your network connection during testing simulates real-world scenarios where users may have slower internet speeds. Monitoring the network waterfall allows you to identify potential bottlenecks and ensure images load correctly.

What are CLS/LCP metrics, and how do they relate to lazy loading implementation?

Core Web Vital metrics like Cumulative Layout Shift (CLS) and Largest Contentful Paint (LCP) measure the visual stability and load performance of a webpage. Lazy loading should be implemented in a way that doesn't negatively impact these critical metrics.

▶ Try it live

Everything above runs in your browser — open Hash Function Avalanche Visualizer and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Hash Function Avalanche Visualizer simulation