WebP or AVIF images: choosing the right format can significantly reduce visual file size, improve load times, and strengthen a website’s SEO performance.
Images often account for a major share of the data loaded by a web page. On an e-commerce site, a news media outlet, or a business application, a few hundred kilobytes saved per image can change the user experience.
The choice between WebP and AVIF is not just a simple either-or. WebP remains very robust and widely compatible, while AVIF pushes compression further, especially for high-quality static images.
WebP or AVIF images: the quick choice based on your needs
For most sites, WebP remains the easiest format to deploy in production. It effectively replaces JPG and PNG in many cases, with good visual quality, possible transparency, and very broad compatibility with modern browsers.
AVIF becomes more interesting when absolute priority is maximum compression. It is especially well suited for static images, edited photos, large hero images, and catalogs where every kilobyte counts.
A web and mobile agency like DualMedia often favors a progressive approach: AVIF when it makes sense, WebP as a fallback, then JPG or PNG for older environments. This strategy avoids broken images while maximizing performance gains.
| Criteria | WebP | AVIF |
|---|---|---|
| Compression | Very good, often smaller than JPG and PNG | Excellent, often more compact than WebP at similar quality |
| Compatibility | Very broad across modern browsers | Good in recent versions, more limited in some older environments |
| Transparency | Yes | Yes |
| Animation | Yes | Yes, depending on the tools and use cases |
| Encoding time | Fast and suited to frequent workflows | Slower, especially for bulk or real-time processing |
| Ideal use case | General website, WordPress, e-commerce, web application | Optimized static images, pages with high performance stakes |
The most reliable decision is therefore to start from the actual use case. A product sheet, a photo gallery, or a hero image do not always follow the same technical constraints.
Why modern formats speed up a website
JPG and PNG have long dominated the web, but they no longer always meet current performance requirements. Mobile connections, Core Web Vitals, and screen density demand lighter images that are better sized and adapted to the device.
WebP, developed by Google, is based on lossy or lossless compression. It can handle photographs, images with transparency, and some animations, making it a very versatile format.
AVIF is based on the AV1 video codec. It offers highly efficient compression, supports transparency, and can handle advanced colors, especially in contexts where perceived quality must remain high despite a smaller file size.
The gain does not come from the format alone. It also depends on resizing, export quality, lazy loading, caching, the CDN, and the way images are served in HTML.
WebP vs AVIF comparison for compression and quality
At equivalent visual quality, AVIF often produces smaller files than WebP. This difference becomes noticeable on large photos, rich backgrounds, marketing campaign visuals, or pages that load many images.
WebP, however, retains an important operational advantage: it encodes faster and integrates easily into CMSs, media libraries, and WordPress plugins. For a team that publishes a lot, this advantage can tip the balance.
A conversion example illustrates the gap well. For a standard product photo, a 340 KB JPG can drop to around 210 KB in WebP, then to around 155 KB in AVIF, with similar perceived quality depending on the settings.
| Format | Common use | Approximate file size | Point to note |
|---|---|---|---|
| JPG | Legacy photos or universal fallback | Larger than WebP and AVIF | No transparency, possible artifacts |
| PNG | Logos, screenshots, transparency | Often heavy for photos | Not well suited for large photographs |
| WebP | General web images, products, screenshots | Often 25 to 35% lighter than a comparable JPG | Quality to adjust based on the type of visual |
| AVIF | Static photos, heavy visuals, advanced optimization | Often 20 to 50% lighter than WebP depending on the case | Slower encoding and a fallback strategy is necessary |
| SVG | Logos, icons, vector illustrations | Very lightweight for simple shapes | Not suitable for photographs |
These rough guidelines should not be applied blindly. A highly detailed image, a screenshot with flat colors, or an animation will not respond to compression in the same way.
Browser compatibility: why WebP remains reassuring
Compatibility is a decisive factor, because an image that fails to load immediately hurts the user experience. WebP now enjoys very broad support across Chrome, Firefox, Edge, Safari, and most modern browsers.
AVIF is also well supported in recent versions of Chrome, Firefox, Safari, and Edge. However, some older environments, embedded browsers, or specific contexts can still pose a problem.
For this reason, progressive delivery remains the cleanest method. The browser receives AVIF first if it can handle it, otherwise WebP, then JPG or PNG as a last resort.
In HTML, the picture element makes this logic possible without JavaScript. It improves rendering robustness while allowing each browser to select the best available file.
Which format should you choose based on the type of image
The best format depends on the visual content. A photograph, an icon, a screenshot, and an animation should not follow the same delivery rule.
For a fictional booking site named NovaTrip, large destination photos are worth testing in AVIF. Result thumbnails can remain in WebP, since their volume is significant and they need to be generated quickly.
- Editorial photographs: AVIF as the priority, WebP then JPG as fallback.
- Product photos: WebP by default, AVIF if the catalog is very large and well automated.
- Logos and icons: SVG as the priority, PNG as fallback if needed.
- Screenshots: WebP to reduce file size, PNG if perfect sharpness is essential.
- Simple illustrations: SVG if they are vector, WebP if they are rasterized.
- Short animations: animated WebP can replace some very heavy GIFs.
This logic avoids overly broad decisions. It links the format to its use, the expected quality, and production cost.
| Content type | Format recommended | Fallback format |
|---|---|---|
| Cover photo | AVIF | WebP then JPG |
| Product photo | WebP | JPG |
| Logo | SVG | PNG |
| Icon | SVG | PNG |
| Screenshot | WebP | PNG |
| Decorative background | WebP or AVIF | JPG |
| Light animation | WebP | GIF |
The right trade-off therefore is not to replace an entire media folder with a single format. It means industrializing several coherent outputs for each type of image.
SEO impact of WebP or AVIF images on Core Web Vitals
Images directly influence Largest Contentful Paint, often called LCP. If the main image on a page is too heavy, the perceived rendering slows down and the user waits longer before seeing the essential content.
Google takes page experience into account in its ranking ecosystem. The image format is not a magical standalone factor, but it is part of an optimization chain that affects speed, visual stability, and accessibility.
To avoid Cumulative Layout Shift, you should always define the width and height attributes. This simple practice reserves space for the image before it loads and limits layout shifts.
On WordPress, a redesign technical issue is often an opportunity to review the entire media chain: generated sizes, compression, CDN, cache, lazy loading, and templates. The DualMedia teams support this type of project with a comprehensive approach to website redesign and long-term performance.
SEO doesn’t stop at image files. Alt tags, the edoritorial context, file names, and the quality of the internal networking remain essential, as reminded by the fundamental principles of organic search optimization.
Technical best practices for serving WebP and AVIF
The most reliable strategy relies on gradual improvement. The site should first offer the most performant format, then provide compatible alternatives.
It is also important to avoid converting all images with a single quality level. A dark photo, a portrait, an interface screenshot, and a colorful illustration require different settings.
- Export images at the actual displayed size, without sending a 3000 px visual for a 400 px thumbnail.
- Use responsive images with srcset to adapt the file to the screen.
- Reserve AVIF for static media where compression provides a real benefit.
- Keep WebP as the primary operational format for sites with frequent publishing.
- Add loading=”lazy” to images below the fold.
- Use fetchpriority=”high” on the LCP image when it is critical.
- Set width and height to stabilize the layout.
- Regularly monitor performance with a reliable measurement tool.
An audit via PageSpeed Insights helps identify images that are too large, incorrectly sized, or loaded too early. To go further, the Google PageSpeed Insights guide helps connect technical recommendations with field metrics.
On complex platforms, automation quickly becomes essential. Build pipelines, compression plugins, image CDNs, and certain AI-based tools can generate multiple formats without slowing editorial production.
WordPress, e-commerce, and mobile apps: cases where the format really matters
On WordPress, images pile up quickly: articles, thumbnails, sliders, service pages, portfolios, and media libraries. A well-configured conversion to WebP, with AVIF for the heaviest visuals, can significantly improve browsing.
In e-commerce, product photos repeat across listings, product pages, recommendations, and search results. Saving a few dozen kilobytes per image becomes significant when a page displays twenty or thirty products.
In a web or mobile app, the issue is even more sensitive. Users may be accessing the service on unstable 4G, on an older device, or in a context where every second counts.
DualMedia often works on these trade-offs between quality, bandwidth, SEO, and user experience. The goal is not just to compress, but to deliver the right media, at the right time, to the right device.
For projects where speed is a business lever, media optimization ties into the broader challenges of loading speed for web and mobile applications.
When to avoid AVIF despite its superior compression
AVIF is not always the best operational choice. Its encoding can be slower, which makes real-time generation or workflows that process large volumes of images on the fly more difficult.
On an editorial site with a lot of daily posts, WebP can offer a more stable balance. The time saved on the production side and the broad compatibility sometimes make up for the slightly lower compression.
Some contexts also remain less favorable to modern formats. Older email templates, for example, handle JPG or PNG better, because email clients do not always follow the same standards as web browsers.
You also need to check visual quality. On some images, AVIF can produce a different rendering in very textured areas or subtle gradients if the settings are too aggressive.
Recommended workflow for converting without losing control
A good process starts with an inventory. You need to identify the heaviest images, the most visited pages, the files loaded above the fold, and redundant media.
Next, batch processing makes it possible to generate several versions: AVIF, WebP, and fallback format. Professional tools or image optimization services also make it possible to adjust quality, resize, rename, and sometimes apply watermarks.
The recipe should include visual testing. Successful compression is measured not only by file size, but also by how it looks on mobile, desktop, and high-density screens.
- Audit slow pages and identify the images responsible.
- Classify media by type: photo, logo, screenshot, icon, animation.
- Define a fallback rule for each image family.
- Generate WebP and AVIF with appropriate quality levels.
- Set up fallbacks with the picture element.
- Test rendering across multiple browsers and devices.
- Measure LCP, total page weight, and network requests.
- Automate generation to avoid human error.
This method limits risks and makes optimization reproducible. It turns a one-off project into a lasting technical advantage.
Our opinion
The best choice is not WebP or AVIF exclusively, but a controlled combination. WebP should remain the foundation for most sites, because it offers an excellent balance of performance, compatibility, and ease of integration.
AVIF is worth using for strategic, large, or highly visible images, when the team has good control over the generation pipeline and fallback formats. This is especially relevant for high-traffic pages, e-commerce sites, and interfaces where LCP shapes the experience.
To speed up a site without compromising rendering, the right strategy is to serve AVIF first, WebP as a fallback, and JPG or PNG as a last resort. This progressive approach, combined with an SEO and UX audit, makes it possible to achieve real gains without sacrificing quality.
WebP or AVIF images: which format should you prioritize?
WebP is the best default choice for most sites. It combines excellent compression, very broad compatibility, and simple integration into WordPress, CMSs, and web applications. AVIF becomes priority when maximum compression is sought for well-controlled static images.
Is AVIF always smaller than WebP?
AVIF is often smaller than WebP at equivalent visual quality. However, the difference depends on the image, the compression level, and the tool used. You should test both formats on important visuals before generalizing.
Is WebP compatible with all modern browsers?
WebP is compatible with the vast majority of modern browsers. Chrome, Firefox, Edge, and Safari support it in their recent versions. For older environments, a JPG or PNG fallback is still recommended.
Can AVIF replace JPG and PNG on a website?
AVIF can replace JPG and PNG in some cases, but not always on its own. It works very well for static photos and heavy visuals, but it should be accompanied by a WebP or JPG fallback. For logos and icons, SVG is often still more suitable.
Do WebP or AVIF images improve SEO?
WebP or AVIF images can indirectly improve SEO thanks to better load times. They reduce page weight, favor LCP, and improve the user experience. Search engine optimization also depends on alt tags, editorial context, and technical structure.
What for format should be used for product photos on an e-commerce site?
WebP is often the most practical format for product photos. It offers a good balance between file size, quality, and compatibility, especially for large catalogs. AVIF can be added for strategic pages or very large visuals.
Should all images on a website be converted to AVIF?
It is not necessary to convert all images to AVIF. The format should be reserved for cases where the compression gain justifies the encoding time and fallback handling. A mixed AVIF, WebP, JPG, and PNG strategy remains more reliable.
How do you serve AVIF with WebP as a fallback?
The recommended method is to use the HTML picture element. The browser loads AVIF if it supports it, otherwise WebP, then JPG or PNG as a last resort. This approach does not require JavaScript and makes the display reliable.
Does WebP preserve the transparency of PNGs?
WebP supports transparency. It can therefore replace many PNG files while reducing their file size. For simple logos and icons, SVG remains preferable when the visual is vector-based.
Is AVIF suitable for web animations?
AVIF can handle some animations, but animated WebP is often simpler to use. To replace a large GIF, WebP is generally more practical and better integrated into current workflows. The choice depends on browser support and the available conversion tools.
Which quality setting should I choose for WebP or AVIF?
The right setting depends on the type of image and the expected level of detail. A photo can support heavier compression than an interface screenshot containing fine text. You need to compare the visual result and the final file size rather than follow a single value.
Can an agency help choose between WebP and AVIF?
A web agency can audit images, measure performance, and define an appropriate strategy. DualMedia supports this type of optimization on websites, WordPress, e-commerce, and mobile applications. The goal is to improve speed without compromising visual quality or SEO.
Would you like to get a detailed quote for a mobile application or website?
Our team of development and design experts at DualMedia is ready to turn your ideas into reality. Contact us today for a quick and accurate quote: contact@dualmedia.fr