Why Image Compression Matters for Web Performance
For years, JPEG, PNG, and GIF were the standard, but they’re outdated when it comes to modern web speed requirements. Enter AVIF and WebP—the two leading next-gen image formats that significantly reduce file sizes without sacrificing quality.
In the world of web design, performance is everything. Google’s Core Web Vitals place loading speed, visual stability, and interactivity at the heart of a website’s user experience ranking. A slow-loading site doesn’t just frustrate users—it gets penalised in search rankings, leading to lost visitors and lower conversions.
One of the biggest culprits of slow websites? Unoptimised images.
But which one should you use? Let’s break it down.
AVIF (Advanced Video Image Format) vs. WebP: A Comparison
AVIF: The Future of High-Quality, Small File Size Images
- Superior Compression: AVIF, based on the AV1 video codec, can achieve smaller file sizes with better quality than WebP and JPEG.
- High-Quality Visuals: Preserves fine details, colors, and high-resolution content, making it perfect for photography and high-quality visuals.
- HDR Support: AVIF supports High Dynamic Range (HDR), which enhances colors and brightness beyond what WebP can achieve.
- Lossy & Lossless Compression: Offers flexibility based on your needs.
Downsides of AVIF:
- Limited Browser Support: AVIF is newer, and while adoption is growing, some older browsers don’t support it yet.
- Slower Encoding/Decoding: AVIF requires more computational power to process, which could slightly affect server-side performance.
- Not Ideal for All Image Types: Logos, icons, and illustrations may work better in WebP due to transparency and animation support.
WebP: The Reliable, Well-Supported Image Format
- Wider Browser Support: WebP is an established format with broad browser compatibility, making it a safer choice.
- Good Compression: WebP delivers smaller file sizes than PNG or JPEG while maintaining strong visual quality.
- Transparency & Animation: WebP supports alpha transparency (like PNG) and even animations (like GIF).
- Lossy & Lossless Compression: You can choose between better quality or smaller file size based on your needs.
Downsides of WebP:
- Lower Quality Compared to AVIF: At the same file size, WebP may not preserve details as well as AVIF.
- Limited Color Gamut: WebP doesn’t support HDR, meaning color accuracy can suffer compared to AVIF.
- Less Efficient Compression: AVIF can achieve the same quality with even smaller file sizes.
When to Use AVIF vs. WebP in Web Design
| Use AVIF When… | Use WebP When… |
|---|---|
| You want high-quality images at the smallest possible size. | You need broad browser compatibility. |
| You’re targeting modern browsers that support AVIF. | Your site has logos, icons, or transparent images. |
| You’re dealing with photography, detailed graphics, or HDR images. | You need animations, since AVIF doesn’t support them. |
Why Google (and Other Performance Experts) Recommend Next-Gen Image Formats
Google’s PageSpeed Insights, Lighthouse, and Core Web Vitals all recommend reducing image sizes for better page speed and SEO rankings. Next-gen formats like AVIF and WebP are explicitly recommended by Google as part of best web practices.
In Google’s own words: “Serve images in next-gen formats to reduce image file size and improve loading speed.”
Fast-loading images impact:
- Better SEO rankings (Core Web Vitals reward faster sites).
- Lower bounce rates (users leave slow sites).
- Higher conversions (fast, optimised pages convert better).
Best Practice: Use Both Formats with a Smart Fallback Strategy
To maximise both performance and compatibility, the best practice is to serve AVIF first, with WebP as a fallback.
How to Implement This on Your Website:
Use the <picture> element in HTML to deliver the best possible format based on browser support:
<picture>
<source srcset="image.avif" type="image/avif">
<source srcset="image.webp" type="image/webp">
<img src="image.jpg" alt="Example Image">
</picture>
- Modern browsers get AVIF (best quality, smallest file size).
- Browsers that don’t support AVIF get WebP (good balance of size and compatibility).
- Old browsers fall back to JPEG (ensuring everyone sees the image).
This automated delivery ensures every visitor gets the best possible experience, without you having to compromise quality or speed.
Final Thoughts: AVIF & WebP Should Be Standard for Web Design in 2025
If you’re still relying on JPEGs and PNGs, your website is falling behind.
Using AVIF and WebP together ensures that your website:
- Loads faster, reducing bounce rates.
- Looks sharper, enhancing user experience.
- Gets better SEO rankings, giving you a competitive edge.
💡 The bottom line? Next-gen image formats should be the standard practice for any modern web design—because Google, Core Web Vitals, and performance experts all say so.
Need help optimising your website for speed and performance?
At Rebellion Websites, we build sites that are fast, modern, and SEO-friendly—using AVIF and WebP as standard. Get in touch today and lets make your website lightning fast.