Images

What are images?

Images are visual representations on a web page created from image file formats like GIF, JPEG, PNG, WebP, AVIF, and SVG.

Why images matter for SEO performance

How images are served, as well as their file size and dimensional attributes, affect page speed performance and Core Web Vitals.

Image performance tips

• Attempt to keep image file sizes under 100KB.
• Use dns-prefetch when serving images from a content delivery network (CDN).
• Use modern image formats like WebP and AVIF that compress images while maintaining visual clarity.
• Always specify the width and height, and include the image’s aspect ratio to avoid layout shifts.
• Consider lazy-loading images, but avoid doing it for images displayed within the viewport (above the fold).
• Consider using srcset to serve optimized images per device and screen type.

Image performance resources

• Image optimization guide
• Image performance

Written by Jon Henshaw, published on 04/27/2024, and last updated on 09/3/2024.