WebP vs AVIF vs JPEG: Which Image Format Should You Use?

The image format you choose has a massive impact on file size — sometimes more than any other optimization. Switching from JPEG to WebP alone can reduce file size by 25–35% at the same visual quality. Switching to AVIF can save 40–55%. For a site with dozens of images per page, those savings add up to multiple megabytes.

Quick Comparison

JPEG — The Old Reliable (That You Should Mostly Replace)

JPEG has been the web's default photo format since the 1990s. It works everywhere, it's well-understood, and every tool supports it. But it's no longer the most efficient option for the modern web.

JPEG uses lossy compression, which means it discards some image data to reduce file size. The tradeoff is fine — you control quality with a 0–100 scale — but the compression algorithm is outdated compared to modern alternatives.

When to still use JPEG: When you need to support very old browsers or environments where WebP isn't supported. Otherwise, WebP or AVIF are strictly better choices.

PNG — The Transparency Champion

PNG uses lossless compression, which means no quality loss — ever. This makes it ideal for images that require pixel-perfect accuracy: logos, icons, screenshots, and graphics with text.

The problem with PNG is that lossless compression on photos creates very large files. A photo saved as PNG can be 5–10× larger than the same photo as JPEG or WebP.

Common mistake: Saving photographic images as PNG. Image Inspector flags this as a critical issue — if your PNG image has natural dimensions over 400×400px, it's almost certainly a photo that should be WebP or JPEG.

WebP — The Practical Modern Default

WebP was developed by Google specifically to replace JPEG and PNG on the web. It supports both lossy and lossless compression, handles transparency (like PNG), and achieves significantly smaller file sizes than both.

• vs JPEG: WebP is 25–35% smaller at equivalent quality
• vs PNG: WebP lossless is 26% smaller; lossy WebP is 60–70% smaller for photographic PNG content
• Browser support: 97%+ of all browsers as of 2026

WebP is the safest modern format choice. It's supported everywhere that matters, the tooling is mature, and the savings are substantial. If you can only do one format optimization, switch to WebP.

AVIF — The Next-Generation Format

AVIF is based on the AV1 video codec and represents the current state-of-the-art in image compression. It consistently outperforms WebP by another 20–30% in file size while maintaining superior quality — especially at low bitrates.

• vs JPEG: AVIF is 40–55% smaller at equivalent quality
• vs WebP: AVIF is 20–30% smaller
• Browser support: ~90% as of 2026 (Chrome, Firefox, Safari 16+, Edge)

The main trade-off is encoding speed. AVIF takes noticeably longer to encode than WebP, which matters if you're generating images on-the-fly. For static assets, this is a one-time cost and AVIF is the better choice.

Use AVIF for high-quality hero images and product photos where maximum compression matters. Use WebP as your fallback. Use <picture> with <source> elements to serve the right format to each browser.

GIF — Only for Animation (And Even Then, Consider Alternatives)

GIF is 1987 technology. Its color palette is limited to 256 colors, and even for animations, it produces large files. The only valid reason to use GIF today is for simple animations that need to loop automatically without JavaScript.

For static images, never use GIF. For animations, consider WebP (which supports animation), AVIF (animation support is improving), or video formats (MP4, WebM) — which are consistently 80–95% smaller than animated GIFs.

SVG — The Right Choice for Icons and Logos

SVG is a vector format — it scales to any size without losing quality and is defined in code (XML). For logos, icons, illustrations, and any graphic that needs to look sharp at any resolution, SVG is almost always the right choice.

SVG files are also directly editable and can be embedded inline in HTML, which eliminates the HTTP request entirely. Image Inspector notes SVG images but doesn't flag them for optimization — they're already the correct format.

How to Implement Multiple Formats with <picture>

The HTML <picture> element lets you offer multiple formats and let the browser pick the best one it supports:

<picture>
  <source srcset="hero.avif" type="image/avif">
  <source srcset="hero.webp" type="image/webp">
  <img src="hero.jpg" alt="Hero image" width="1200" height="630">
</picture>

Browsers that support AVIF use it, browsers that support WebP use that, and older browsers fall back to JPEG. No JavaScript needed.

Practical Decision Guide

• Photos: AVIF first, WebP fallback, JPEG as legacy fallback
• Graphics/logos: SVG (if possible), then WebP lossless or PNG
• Animations: WebP or MP4/WebM, never GIF
• Screenshots: WebP or PNG depending on quality needs