Responsive Images & Lazy Loading
Implement responsive image techniques using `srcset` and `sizes`, and leverage lazy loading for off-screen media.
Why Responsive Images?
Imagine browsing a website on a tiny phone screen, but the site loads an image meant for a huge desktop monitor. That's a waste of data and makes the page slow!
Responsive images ensure users get images optimized for their specific device and screen size, improving performance and user experience.
`srcset` for Resolution
The srcset attribute allows you to provide a list of different image files for the browser to choose from. One way to use it is for resolution switching.
This means serving higher-resolution images to devices with high-DPI (Retina) screens and standard resolution images to others.
1x: Standard resolution2x,3x: Higher resolutions
<img src="cat-1x.jpg" srcset="cat-1x.jpg 1x, cat-2x.jpg 2x" alt="A cute cat" />All lessons in this course
- Efficient Image Formats
- Responsive Images & Lazy Loading
- Video and Animation Performance
- Image CDNs and Delivery Optimization