WebP vs AVIF: Which Image Format Is Better for WordPress?

Choosing the right image format can have a noticeable impact on WordPress website performance.

Images are often among the largest files loaded by a webpage, especially on websites that use large hero images, product photos, blog graphics, portfolios, or background images. Using a modern image format can reduce file sizes, improve loading performance, reduce bandwidth usage, and help create a better experience for visitors.

Two of the most important modern formats are WebP and AVIF.

Both can provide significantly better compression than traditional JPEG and PNG images. However, they are not identical. AVIF can often produce smaller files at similar visual quality, while WebP offers a mature workflow and broad browser support.

So which one should you use on a WordPress website?

The answer depends on your images, WordPress setup, optimization tools, browser support requirements, and how your website serves images.

In this guide, you will learn the differences between WebP vs AVIF, how each format affects WordPress performance, when to use each one, and how to choose the right format for your website.

What Is WebP?

WebP is a modern image format developed by Google.

It supports both lossy and lossless compression, as well as transparency and animation. Compared with older formats such as JPEG and PNG, WebP can often produce significantly smaller files while maintaining similar visual quality.

WordPress has supported WebP uploads since WordPress 5.8, making the format relatively easy to use on modern WordPress websites.

For example, a JPEG image might look like this:

hero-image.jpg

The same image could be converted to:

hero-image.webp

If the WebP version provides similar visual quality at a smaller file size, the browser can download less data.

That can help reduce the amount of data required to display the page.

Advantages of WebP

WebP offers several useful features for WordPress websites:

• Smaller files than many JPEG and PNG equivalents
• Lossy and lossless compression
• Transparency support
• Animation support
• Broad modern browser support
• Native WordPress support
• Good compatibility with image optimization plugins and CDNs

According to MDN, WebP images are typically smaller than visually similar JPEG images, while also supporting transparency and lossless compression.

This makes WebP a practical default for many WordPress websites.

What Is AVIF?

AVIF stands for AV1 Image File Format.

It is a newer image format based on the AV1 video codec and is designed to provide highly efficient image compression.

AVIF supports both lossy and lossless compression, transparency, animation, high color depths, HDR, and wide color gamuts.

For many images, AVIF can achieve a smaller file size than WebP while maintaining comparable visual quality.

For example:

hero-image.jpg

could potentially become:

hero-image.avif

with a substantially smaller file size.

However, smaller does not automatically mean better for every website.

AVIF encoding can be more demanding, and depending on the image and quality settings, the visual difference between AVIF and WebP may be small.

There is also an important consideration when implementing AVIF: fallbacks.

WebP vs AVIF: What Is the Difference?

The biggest difference is the balance between compression efficiency, compatibility, and implementation.

Feature	WebP	AVIF
Compression	Very good	Often better
Lossy compression	Yes	Yes
Lossless compression	Yes	Yes
Transparency	Yes	Yes
Animation	Yes	Yes
Modern browser support	Very broad	Very broad
Encoding complexity	Generally lower	Generally higher
WordPress support	Yes	Yes
Best use	General-purpose web images	Maximum compression when supported

Both formats are excellent choices.

The question is not simply whether AVIF is technically more efficient than WebP.

The better question is:

Which format provides the best balance for your particular WordPress website?

Is AVIF Smaller Than WebP?

In many cases, yes.

AVIF generally provides stronger compression than WebP for similar visual quality. MDN describes AVIF as offering better compression than WebP in many cases, while WebP remains a highly efficient format with broad support.

For example, imagine you have a JPEG image that is 300 KB.

After optimization, you might get results such as:

• JPEG: 300 KB
• WebP: 180 KB
• AVIF: 140 KB

These numbers are only an example. Actual results depend heavily on the original image, dimensions, compression settings, image content, and quality target.

A photograph, screenshot, illustration, and product image can all produce very different results.

That is why you should test the actual image rather than assuming one format will always be smaller.

Is WebP Better Than AVIF?

Not necessarily.

WebP can be the more practical option when you want a simple, reliable workflow with excellent browser compatibility.

AVIF can be preferable when reducing image file size is a major priority and your image optimization setup can reliably generate and serve it.

For many WordPress websites, there is no reason to choose only one format.

You can use AVIF where it performs well and maintain WebP or another fallback where necessary.

Modern HTML provides the <picture> element specifically for cases where different image formats or fallbacks need to be offered to browsers.

Browser Support: WebP vs AVIF

Browser support is one of the reasons WebP became such a common recommendation for WordPress websites.

Modern versions of Chrome, Edge, Firefox, Safari, and other major browsers support WebP. AVIF is also supported by modern versions of major browsers, but it has less historical browser support.

This distinction matters less today than it did several years ago, but it is still relevant when building websites for a broad audience.

If your website serves AVIF images, you should make sure that your implementation can provide an appropriate fallback.

A simplified example looks like this:

<picture>
    <source srcset="image.avif" type="image/avif">
    <source srcset="image.webp" type="image/webp">
    <img src="image.jpg" alt="Example image">
</picture>

The browser can select a format it supports, while the <img> element provides the fallback.

You do not necessarily need to write this code manually. Many WordPress optimization plugins and image delivery systems can handle modern image formats automatically.

Does WordPress Support WebP?

Yes.

WordPress introduced native WebP support in WordPress 5.8. This allows WebP images to be uploaded and used similarly to other supported image formats.

However, simply uploading a WebP image does not automatically mean your website is fully optimized.

You still need to consider:

• Image dimensions
• Compression quality
• Responsive image sizes
• Lazy loading
• Image delivery
• Largest Contentful Paint
• CDN configuration
• Caching
• Above-the-fold images

A badly sized WebP image can still be unnecessarily large.

For example, converting a 4000 × 3000 pixel photograph to WebP does not solve the problem if the image is displayed at only 800 × 600 pixels.

The format matters, but image dimensions matter too.

Does WordPress Support AVIF?

Modern WordPress versions support AVIF when the server’s image processing capabilities support the format.

WordPress includes AVIF in its supported image MIME types, but the ability to process AVIF images can depend on the image library available on the hosting environment.

This is important because there are two separate questions:

1. Can WordPress accept the image format?
2. Can your server generate and process that format?

Your hosting environment, PHP image processing library, optimization plugin, and CDN can all affect the answer.

If AVIF generation is unavailable, your optimization plugin may continue using WebP or another supported format.

WebP vs AVIF for WordPress Performance

Image format can affect performance because smaller images generally require less data to transfer.

However, image format is only one part of WordPress performance.

A website with AVIF images can still be slow because of:

• Slow hosting
• High TTFB
• Render-blocking CSS
• Excessive JavaScript
• Poor caching
• Large DOM size
• Unoptimized fonts
• Too many plugins
• Slow database queries
• Poor CDN configuration

This is why image optimization should be treated as one part of a larger performance strategy.

For a complete overview of WordPress performance optimization, see our main guide:

How to Speed Up a WordPress Website: Complete Optimization Guide

That guide covers image optimization alongside caching, CSS, JavaScript, hosting, Core Web Vitals, and other performance factors.

Which Format Is Better for Hero Images?

Hero images deserve special attention because they are often part of the initial viewport.

If the hero image becomes the Largest Contentful Paint (LCP) element, its size and loading behavior can directly affect perceived loading performance.

In this situation, you should not simply convert the image to AVIF or WebP and assume the problem is solved.

Instead, check:

• Actual displayed dimensions
• File size
• Compression quality
• Image priority
• srcset and responsive images
• Preloading where appropriate
• CDN delivery
• Server response time
• Whether lazy loading is incorrectly applied

For an LCP image, lazy loading can sometimes delay the image that the visitor needs immediately.

The goal is not simply to use the newest image format.

The goal is to make the right image available to the browser as quickly as possible.

Which Format Is Better for WordPress SEO?

Neither WebP nor AVIF is a magic SEO ranking factor.

Their main SEO benefit is indirect: they can help reduce image weight and improve page performance.

Faster-loading pages can provide a better user experience, particularly on mobile connections.

However, changing JPEG images to WebP or AVIF does not automatically improve rankings.

You should still optimize:

• Image dimensions
• Alt text
• File names
• Responsive images
• Image quality
• Loading behavior
• Page performance

For example, an image should not have an alt attribute such as:

image12345.webp

If the image communicates meaningful information, its alt text should describe that purpose.

The file format and accessibility metadata solve different problems.

WebP vs AVIF for WooCommerce

WooCommerce stores often contain many images.

Product galleries, thumbnails, category images, banners, and promotional graphics can quickly increase the amount of data a visitor needs to download.

Modern image formats can therefore be particularly useful for WooCommerce.

For product images, test both WebP and AVIF when your optimization system supports them.

Pay attention to:

• Product image quality
• Zoom quality
• Thumbnail clarity
• Mobile performance
• Image dimensions
• Total page weight
• CDN delivery

Do not compress product images so aggressively that product details become difficult to see.

For an online store, image quality is part of the product presentation.

A slightly smaller file is not worth a visibly worse product image.

WebP vs AVIF for Transparent Images

Both WebP and AVIF support transparency.

This makes them useful alternatives to PNG for many graphics that require an alpha channel.

Examples include:

• Logos
• Product cutouts
• Interface graphics
• Illustrations
• Decorative elements

However, SVG is usually a better choice for true vector graphics such as icons and simple logos when an SVG version is available.

For raster images requiring transparency, WebP or AVIF can often provide a much smaller file than PNG.

When Should You Use WebP?

WebP is a strong choice when you want:

• Excellent compression
• Broad browser compatibility
• Easy WordPress integration
• Reliable image optimization
• A mature workflow
• Support for transparency
• Support for animation

For many WordPress websites, using WebP for most raster images is already a significant improvement over serving large JPEG and PNG files.

If your current website is still serving large unoptimized JPEG and PNG images, moving to WebP can be a practical first step.

When Should You Use AVIF?

AVIF is worth considering when:

• You want maximum image compression
• Your optimization system supports reliable AVIF generation
• Your visitors use modern browsers
• You can provide an appropriate fallback
• The visual quality remains acceptable
• Your CDN or image delivery system handles AVIF correctly

AVIF can be particularly useful for large photographic images where the reduction in file size is meaningful.

But do not convert every image to AVIF without testing.

A smaller file is useful only if the image still looks good and the delivery system works correctly.

Should You Use WebP and AVIF Together?

For many websites, yes.

Instead of thinking:

WebP OR AVIF

think:

AVIF → WebP → JPEG/PNG fallback

The exact implementation depends on your WordPress plugin, CDN, hosting environment, and browser requirements.

For example, a modern image delivery system might serve AVIF to browsers that support it, WebP to others, and JPEG or PNG as a fallback.

The browser does not need to download every version.

It receives the format appropriate for its capabilities.

This is one reason the <picture> element is useful for format fallbacks.

Should You Convert Every Image to AVIF?

No.

There are several reasons not to blindly convert every image.

First, not every image benefits equally from the same compression settings.

Second, some images may already be very small.

Third, converting an image without checking dimensions does not solve oversized-image problems.

Fourth, an AVIF image that is technically smaller may not provide a meaningful real-world performance improvement if another part of the page is responsible for most of the loading delay.

Always look at the actual page.

For example, if your page has:

• A 150 KB AVIF hero image
• 2 MB of JavaScript
• 900 KB of CSS
• 1.5 MB of third-party scripts

Reducing the hero image from 150 KB to 120 KB may not be the highest-impact optimization.

Performance work should be based on measurements rather than assumptions.

How to Choose Between WebP and AVIF

A simple decision process can help.

Choose WebP when:

• You want a straightforward setup
• You need broad compatibility
• Your optimization plugin works best with WebP
• WebP provides a sufficiently small file
• You want a reliable default format

Choose AVIF when:

• AVIF produces a meaningfully smaller file
• Visual quality remains good
• Your server or optimization service supports it
• Your delivery system handles it correctly
• You have a suitable fallback

Use both when:

• You want to serve the smallest practical format
• Your image optimization system supports format negotiation
• You can provide fallbacks
• You want a flexible setup for different browsers

How to Test WebP vs AVIF

Do not compare formats only by looking at the file extension.

Take the same original image and create:

• JPEG
• WebP
• AVIF

Then compare:

• File size
• Visual quality
• Dimensions
• Compression artifacts
• Loading behavior
• Performance on the actual page

For example, you might test:

Original JPEG: 500 KB
WebP: 220 KB
AVIF: 160 KB

If both modern formats look equally good, AVIF may provide the smaller transfer size.

But if the WebP version is 190 KB and the AVIF version is 170 KB, the difference may not justify a more complicated setup depending on your website.

The correct choice is based on the complete implementation, not just the smallest possible number.

Image Quality Matters More Than the Format

A common mistake is focusing too heavily on the file format while ignoring compression quality.

You can create a badly optimized WebP image.

You can also create a badly optimized AVIF image.

For example, excessive compression can introduce:

• Blurry details
• Blocking
• Color banding
• Loss of texture
• Visible artifacts around text
• Poor product image quality

The goal is to find the point where the file is significantly smaller without creating noticeable quality problems.

For photographs, lossy compression is often appropriate.

For screenshots, diagrams, text-heavy graphics, and line art, compression artifacts can be much more noticeable. MDN recommends considering lossless encoding for images where sharp edges and precise details are important.

Do WebP and AVIF Improve Core Web Vitals?

They can help, but indirectly.

Reducing image file sizes can reduce the amount of data that needs to be transferred and can help images load faster.

That can be particularly relevant to Largest Contentful Paint (LCP) when a large image is the LCP element.

However, Core Web Vitals are influenced by many other factors.

For example:

LCP can be affected by:

• Server response time
• Render-blocking resources
• Image loading
• Resource discovery
• Client-side rendering

INP can be affected by:

• JavaScript execution
• Long tasks
• Event handlers
• Third-party scripts

CLS can be affected by:

• Images without dimensions
• Dynamic content
• Fonts
• Ads and embeds

Therefore, switching from WebP to AVIF will not automatically fix Core Web Vitals.

It is one optimization within a larger performance process.

Common Image Optimization Mistakes

1. Using modern formats but huge dimensions

A 4000-pixel image can still be unnecessarily large even when it is WebP or AVIF.

Resize images according to their actual display requirements.

2. Compressing the image too aggressively

Smaller is not always better if the image becomes visibly degraded.

3. Lazy loading the LCP image

Important above-the-fold images should be handled differently from images lower on the page.

4. Serving multiple full-size images

Responsive images allow browsers to select a more appropriate image size for the device.

5. Ignoring the CDN

A highly optimized image can still take longer to reach the visitor if it is served inefficiently from a distant server.

6. Installing several image optimization plugins

Running multiple plugins that all rewrite, compress, or convert images can create conflicts and duplicate processing.

Choose one primary image optimization workflow and make sure your caching and CDN setup works with it.

7. Optimizing images without measuring

Always test the actual page before and after the change.

A smaller image file does not automatically mean the entire page is faster.

How WebP and AVIF Fit Into a WordPress Performance Strategy

Image optimization should be part of a broader performance workflow.

A practical WordPress performance process can look like this:

1. Measure the website

Run performance tests and identify the largest problems.

2. Check TTFB

If the server response is slow, image optimization alone will not solve the underlying issue.

3. Optimize images

Resize images and use WebP or AVIF where appropriate.

4. Optimize CSS and JavaScript

Reduce unnecessary resources and address render-blocking files.

5. Configure caching

Use page caching and appropriate browser caching.

6. Review the CDN

Make sure static assets are delivered efficiently.

7. Re-test

Compare the results after each major change.

This approach is more effective than installing an optimization plugin and enabling every option without checking what it actually changes.

If you are troubleshooting server response time specifically, see our guide:

How to Fix High TTFB in WordPress: Complete Server Response Time Guide

TTFB and image optimization are related to overall performance, but they solve different parts of the loading process.

WebP vs AVIF: Which One Should You Use?

There is no universal answer that applies to every WordPress website.

WebP is an excellent general-purpose choice because it provides strong compression, broad browser support, and straightforward WordPress integration.

AVIF can provide even better compression and can be an excellent option when your server, optimization plugin, CDN, and fallback strategy support it properly.

For many websites, the most practical approach is to support both.

Use AVIF when it provides a meaningful benefit, WebP as a strong modern fallback, and JPEG or PNG when necessary.

Most importantly, optimize the image itself, not just the file format.

The right dimensions, compression quality, loading strategy, caching, and delivery method can have a larger impact than simply changing the extension.

Final Checklist

Before publishing images on a WordPress website, check:

• Is the image correctly sized?
• Is it compressed?
• Can WebP reduce the file size?
• Can AVIF reduce it further without visible quality loss?
• Does the website provide a fallback where necessary?
• Is the LCP image loaded appropriately?
• Are below-the-fold images lazy loaded?
• Are responsive image sizes being used?
• Is the CDN configured correctly?
• Have you tested the actual page after optimization?

The goal is not to use the newest format simply because it is newer.

The goal is to deliver the smallest practical image at the right quality and size to the right visitor.

Want to Improve More Than Just Your Images?

Image optimization is only one part of building a fast WordPress website.

Once you start looking at performance as a complete system, factors such as hosting, caching, server response time, CSS, JavaScript, databases, themes, plugins, and Core Web Vitals all become part of the process.

If you want a broader understanding of how these pieces work together, the WP Flow Mastery WordPress eBook is a 160+ page practical guide covering WordPress hosting, development, website performance, SEO, security, WooCommerce, optimization, and other essential areas of professional WordPress work.

Instead of relying on scattered tutorials for every individual problem, you can use one structured resource to build a stronger understanding of the complete WordPress workflow.

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Written by Nemanja Stosic

WordPress Developer & Website Optimization Specialist

Nemanja has worked on more than 200 websites and focuses on WordPress development, performance optimization, SEO, security, WooCommerce, and practical website improvements.