For Website Image Compression, Should You Choose WebP or AVIF to Improve Speed?

Should You Choose WebP or AVIF for Website Image Compression to Improve Speed?

When optimizing website speed, “Should website images be compressed using WebP or AVIF?” is almost an unavoidable question in technical evaluations. It may seem like simply switching file formats, but it actually affects above-the-fold loading, server transcoding load, browser compatibility, CDN caching strategies, and the delivery practices of design teams. This is especially true for independent websites targeting overseas markets, where visitors’ network environments, device performance, and browser versions vary more widely. You cannot judge based only on which format produces a smaller file for a single test image.

Here is the conclusion first: if the goal is to minimize the transfer size of high-quality images as much as possible, AVIF usually has an advantage; if mature compatibility, batch-generation efficiency, and reliable delivery matter more, WebP remains the practical mainstay for most websites. For marketing websites, a more prudent approach is often not to choose one over the other, but to deliver AVIF and WebP in tiers while retaining JPEG or PNG as a fallback.

Do Not Compare File Size Alone: What Really Affects Image Speed Is How Quickly Users See Content

Technical teams often convert the same JPEG into WebP and AVIF separately, then compare file sizes. This test is valuable as a reference, but it cannot be directly equated with a page performance conclusion. User experience concerns the entire process from image request to decoding, rendering, and appearing in the visible area. An AVIF file may be smaller, but it will not necessarily render faster on all low-performance devices, as its encoding and decoding complexity is usually higher.

For example, the homepage of a foreign trade manufacturing company often features a large factory scene image. It must preserve metal textures and equipment details while also serving as the above-the-fold visual. If this type of image is still delivered directly as an oversized JPEG, network transfer is often the primary bottleneck; converting it to AVIF can usually reduce the transfer burden. However, if the above-the-fold image dimensions are already reasonably controlled and many visitors use mobile devices with average specifications, excessively pursuing extremely low bitrates may lead to decoding time, smeared details, or visual delays. The decision for above-the-fold images should be based on actual LCP performance on the live page, rather than compression ratio alone.

Another easily overlooked point is that many images are “slow” not because of their format, but because the original image dimensions are out of control. A product image displayed at only 750 pixels wide on a page may still send a 3000-pixel original image to mobile devices. Even the most advanced format can only mitigate this issue and cannot solve it at the root. Responsive images, correct width and height attributes, CDN cropping, and above-the-fold resource prioritization usually need to be implemented together with format selection.

What Types of Image Tasks Are WebP and AVIF Each Suitable For?

The value of WebP does not lie in it being “older technology,” but in its greater engineering certainty. It supports lossy compression, lossless compression, transparent backgrounds, and animation, and website-building systems, image-processing services, and content management backends are generally well adapted to it. For B2C cross-border stores with many SKUs and frequently updated images, WebP can reduce complexity in batch transcoding and publishing. If a page contains hundreds or thousands of product thumbnails, consistently producing images at appropriate sizes is often more important than compressing every image to its theoretical limit.

AVIF is better suited for areas where “every bit of saved file size is worthwhile.” High-quality photography, people, architecture, industrial equipment, complex backgrounds, and color gradients typically demonstrate its advantages more clearly than simple icons. However, AVIF is not inherently suitable for all visual assets. For icons, logos, or interface elements with simple lines and clearly defined color blocks, SVG is often a more appropriate priority; source files that need to be edited, reviewed, and repeatedly reused should not be replaced simply because the delivery format has changed.

When Deploying Overseas Websites, Compatibility and Fallback Strategies Matter More Than the Format Itself

For websites targeting different markets such as North America, Europe, Southeast Asia, and the Middle East, you cannot assume that every visitor uses the latest browser. AVIF availability in modern browsers has improved significantly, but older system environments, embedded browsers, or enterprise network devices may still be encountered in corporate websites and industrial procurement scenarios. While the risk of images failing to display when only AVIF is provided is not a mainstream scenario, it can still affect critical inquiry pages.

A more reliable approach is to use <picture> to provide multi-format resources: browsers that support AVIF should receive AVIF first, followed by WebP, with JPEG or PNG as the final fallback. The server can also negotiate the format based on browser request headers, but this route requires careful checking of CDN cache rules. If the cache does not properly distinguish different Accept request headers, AVIF may be incorrectly served to devices that do not support it, making troubleshooting far from easy.

In the day-to-day maintenance of intelligent website building and multilingual websites, original assets should also be retained. Compressed formats are delivery versions, not the only versions in the asset library. When changing themes later, adapting to new screen sizes, creating social media assets, or integrating new image services, only the availability of original images can prevent quality loss caused by “recompressing already compressed images.”

For Above-the-Fold Images, Product Images, and Content Images, Different Trade-Offs Are Recommended

In actual projects, the least recommended approach is to “convert the entire website to AVIF with one click and then consider the optimization complete.” Resources can be handled by role: for above-the-fold hero visuals, first test both AVIF and WebP and observe loading and LCP on real devices; for large product images on detail pages, provide multiple size versions according to detail requirements to prevent mobile devices from downloading desktop-grade images; WebP is usually sufficient for list thumbnails; non-above-the-fold content images can be lazy-loaded, but do not mistakenly enable lazy loading for core above-the-fold images.

Quality settings should not be standardized across the entire website either. A product image on a white background, a portrait banner, and an equipment nameplate with dense text have entirely different tolerances for compression artifacts. In particular, when images contain parameter tables, packaging labels, or process-flow text, readability should take priority; such content may sometimes be better split into HTML text and images instead of baking all key information into a single large image.

From Website Building to Marketing, Image Formats Need to Be Included in Ongoing Governance

When Yiyingbao provides services such as intelligent website building, cross-border stores, SEO, and advertising marketing for foreign trade enterprises and overseas brand expansion projects, image optimization should generally not be treated as a one-time cleanup before launch. Advertising landing pages frequently change creative assets, social media traffic-driving pages may experience concentrated traffic in the short term, and multilingual websites also generate new images as content is updated for different markets. Format strategies, dimension rules, naming standards, CDN processing, and quality reviews need to be incorporated into the website-building publishing process rather than addressed only after speed alerts occur.

If a technical team can only choose one default format first, WebP is usually the lower-risk starting point; if a complete image-processing workflow, CDN capabilities, and format fallback mechanisms are already in place, then AVIF is worth using for high-value visual assets. What truly helps improve speed is not blindly pursuing smaller files, but ensuring that every device receives the image it needs and that key pages render properly in every foreseeable browsing environment.