WebP vs AVIF: Choosing the Right Website Image Format

Images are often the heaviest part of a web page. Choosing a modern format can make pages load faster without a visible drop in quality. This guide compares WebP vs AVIF alongside the older JPEG, PNG and SVG formats.

The main formats

• JPEG: the old standard for photos. Widely supported, decent quality at moderate file sizes.
• PNG: good for graphics needing transparency or sharp edges, but files can be large for photos.
• WebP: a modern format that supports photos, transparency and animation. Typically produces smaller files than JPEG or PNG at similar quality. Browser support is very broad today.
• AVIF: a newer format that can compress even smaller than WebP in many cases, with good quality. Support is wide in current browsers, though encoding can be slower and tool support varies.
• SVG: a vector format for logos and simple icons. It scales cleanly and is usually tiny.

Which format for which job?

1. Photos and banners: AVIF or WebP, with a JPEG fallback if you need older browser support.
2. Logos and icons: SVG where possible.
3. Screenshots with text: WebP or PNG, and check the text stays crisp.
4. Transparent graphics: WebP, AVIF or PNG.
5. Animations: consider short video instead of large animated files.

Results depend on the image, so test your own files rather than trusting a rule of thumb.

Practical workflow

• Resize images to the largest size they actually display. A 4000 pixel photo shown at 800 pixels wastes data.
• Export to WebP or AVIF using a tool such as Squoosh, your CMS or an image plugin.
• Use responsive images with srcset so phones get smaller versions.
• Serve a fallback format using the picture element when needed.
• Lazy-load images below the fold, but not the main hero image.
• Always add descriptive alt text. See image SEO best practices.

Quality settings

Do not over-compress. Compare the original and compressed version at full size. If you notice banding or blur on faces and text, raise the quality a little.

Impact on performance

Smaller images help the page load sooner, which supports Core Web Vitals such as Largest Contentful Paint. Learn more in Core Web Vitals explained and website speed optimization tips.

Hypothetical example

A photographer's portfolio uses 3 MB JPEGs on its homepage. After resizing and converting to WebP with sensible quality, the page transfers far less data, and pages feel quicker on mobile networks.