If you are working on a React application, images are usually one of the first things I look at when trying to improve page performance.
A large JPEG or PNG image can easily be hundreds of KB or even a few MB. If a page contains multiple images, that can quickly increase the amount of data the browser needs to download.
This is where modern image formats like WebP and AVIF become useful.
Both formats can reduce image size compared with traditional JPEG and PNG images, but they have some differences.
So, which one should you use in a React project?
Let's look at the practical differences.
What is WebP?
WebP is an image format developed by Google.
The main goal of WebP is simple: provide smaller image files without losing too much visual quality.
WebP supports both lossy and lossless compression, as well as transparency and animation.
The actual size will depend on the original image and compression settings, but WebP can provide a significant reduction compared with JPEG.
One reason WebP became popular is that browser support became very good, making it a practical replacement for many JPEG and PNG images.
What is AVIF?
AVIF is a newer image format based on the AV1 video codec.
Its biggest advantage is compression efficiency.
In many cases, AVIF can produce a smaller file than WebP while maintaining similar visual quality.
If your website contains a lot of photographs or large images, reducing the file size can save a significant amount of bandwidth.
The downside is that AVIF encoding can sometimes require more processing than WebP, depending on the encoder and configuration.
WebP vs AVIF: File Size
If we compare compression efficiency, AVIF will often produce a smaller file.
For example:
Original JPEG: 800 KB
WebP: 500 KB
AVIF: 350 KB
Imagine a product page with 20 images.
Even a small reduction per image can make a noticeable difference in the total amount of data downloaded.
This is especially useful for:
E-commerce websites
Photography websites
News websites
Blogs with many images
Image-heavy React applications
However, smaller file size isn't the only thing that matters.
You also need to consider image quality, browser support and how easily you can generate these formats.
Browser Support
Browser support is another important difference.
WebP has been supported by modern browsers for quite a while, so it is generally a safe choice.
AVIF also has broad support in modern browsers, but if your application needs to support older browsers or different environments, providing a fallback is still a good idea.
One common approach is using the element:
<picture>
<source srcSet="/images/photo.avif" type="image/avif" />
<source srcSet="/images/photo.webp" type="image/webp" />
<img
src="/images/photo.jpg"
alt="Example"
/>
</picture>
The browser will choose the first supported format.
So the fallback can look like:
AVIF
↓
WebP
↓
JPEG
This approach lets you use AVIF for browsers that support it while still having a WebP or JPEG fallback.
What About Image Quality?
Both WebP and AVIF can provide very good image quality.
But the format itself isn't the only factor.
The final result depends on things like:
Compression level
Encoder
Image type
Original image quality
Image dimensions
For example, an aggressively compressed AVIF image can look worse than a properly compressed WebP image.
So I wouldn't simply say:
AVIF is better because it is smaller.
A better question is:
Which format gives you the image quality you need at the file size you want?
For large photographs, AVIF can be very effective.
For general website images, WebP may already provide more than enough compression and quality.
Using WebP and AVIF in React
Using modern image formats is only one part of image optimization in React.
For example, you could have a perfectly optimized AVIF image, but if you're loading a 2000px image into a 400px container, you're still downloading more data than necessary.
Responsive images are important too.
For example:
<img
src="/images/product-800.webp"
srcSet="
/images/product-400.webp 400w,
/images/product-800.webp 800w,
/images/product-1200.webp 1200w
"
sizes="(max-width: 768px) 100vw, 800px"
alt="Product"
/>
Now the browser can select an appropriate image size based on the user's device and layout.
You can also combine responsive images with AVIF and WebP using
<picture>.
For example:
<picture>
<source
srcSet="/images/product.avif"
type="image/avif"
/>
<source
srcSet="/images/product.webp"
type="image/webp"
/>
<img
src="/images/product.jpg"
alt="Product"
/>
</picture>
This gives you a practical fallback strategy without forcing every browser to use the same format.
Final Thoughts
So, WebP vs AVIF — which one is better?
There isn't a single answer for every React application.
WebP is mature, reliable and provides good compression with broad browser support.
AVIF can provide even better compression and smaller files, especially for photographs and image-heavy websites.
If your project supports it, using both can be a practical approach:
AVIF
↓
WebP
↓
JPEG/PNG
But don't forget that image optimization is bigger than just choosing a file format.
Test your real images, check the file sizes, compare the visual quality, and measure the actual loading performance.
That's usually the best way to decide.
Related React Smart Image NPM
I also created @concatstring/react-smart-image for React applications. It can automatically try AVIF → WebP → the original image when those formats are available.
<SmartImage
src="/images/banner.jpg"
format="auto"
alt="Banner"
/>
If your CDN or image storage provides the corresponding files:
banner.avif → banner.webp → banner.jpg
You can also use it with image services such as Cloudinary or other CDNs that provide optimized image formats.
The package doesn't convert the images itself. It simply uses the available AVIF/WebP versions and falls back to the original image when needed.
Check it out:
NPM: https://www.npmjs.com/package/@concatstring/react-smart-image
GitHub: https://github.com/concatstring-account/react-smart-image
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