Reposted by John Allsopp
How far ahead browsers fetch lazy images:
• Chrome: 1,250px on 4G, 2,500px on 3G, 6,000px (!!) on 2G
• Firefox: 600px, on any connection
• Safari: one viewport. Lazy iframes: 0px, they wait until on screen
calibreapp.com
Lazy Loading Images and Media: How Far Ahead Browsers Fetch
How far ahead Chrome, Firefox and Safari fetch lazy media, why a lazy hero image slows your page, and where to use lazy, eager and fetchpriority.
