Convert Photos to WebP and AVIF Online: How to Speed Up Your Site and Improve SEO

We prepare images for websites and online stores every day, and we see how much the right format changes load speed. In this article, with no filler, we explain what WebP and AVIF are, when to use each, how they affect SEO, and how to convert a photo online in a minute.

On a typical website, images make up 50 to 70 percent of the entire page weight. Not scripts, not fonts, but images are what drag download size and load time down. When we optimize a project, the first thing we look at is what format the photos are stored in. And almost always it turns out to be plain old JPEG or, worse, a heavy PNG of two or three megabytes. The modern formats WebP and AVIF solve this problem at its root: they show the same picture but weigh one and a half to two times less. Less weight means faster loading, better behavioral metrics and higher positions in search. Below we break it all down: exactly how much lighter the new formats are, how they affect Core Web Vitals and SEO, which browsers support them, when to use each, and how to convert everything without Photoshop or the command line. If you just want the result, you can convert a photo to WebP and AVIF online right away and come back to reading later.

WebP is a format from Google that appeared in 2010. It uses the compression algorithm from the VP8 video codec and can work both with quality loss (as a replacement for JPEG) and without loss (as a replacement for PNG). Its main property: at visually identical quality, a WebP file weighs on average 25 to 35 percent less than JPEG and 25 to 30 percent less than PNG. As a bonus, WebP supports transparency (an alpha channel) and animation, meaning it can also replace GIF, with a large weight advantage.

AVIF is a younger format based on the AV1 video codec, open and free. It compresses more aggressively than WebP: on the same photos, AVIF produces files that are 40 to 50 percent lighter than JPEG, and sometimes more. AVIF handles gradients better (sky, blurred background, skin), produces almost none of the characteristic blocky artifacts, and supports an extended dynamic range (HDR, 10 to 12 bits of color). The trade-off: AVIF encoding is slower, and old devices and browsers do not understand it.

To make it clearer, here are typical numbers from our practice. A product photo of 1200 by 1200 pixels:

• JPEG at quality 85 weighs about 280 to 350 KB;
• WebP of the same visual quality weighs 180 to 230 KB, a saving of about 30 percent;
• AVIF weighs 130 to 170 KB, a saving of 45 to 55 percent.

On a catalog page with 30 to 40 such images, the difference turns from kilobytes into megabytes, and a user on mobile internet feels it immediately. An important nuance: the saving depends on the content. On complex, detailed photos (fabric texture, foliage) the gain is smaller; on simple images with flat fills and gradients, on the contrary, it can reach 70 percent. That is why we always advise not to trust averaged promises but simply to run your own real files through a converter and compare the weight. You can do this online in a minute with an image converter: upload a JPEG, get both formats, and see for yourself how much each weighs. If you need a more general converter between formats, there is a separate format converter, and for a strict weight limit, photo compression works well.

Site speed is not an abstract convenience but a direct ranking factor. Search engines take into account how quickly and stably a page loads. Google formalized this in a set of metrics called Core Web Vitals, and images affect almost every one of them.

LCP (Largest Contentful Paint) is the time it takes to render the largest element in the visible area. On most sites that element is an image: the main banner, a product photo, an article cover. The lighter that file, the sooner it renders. Replacing a JPEG with an AVIF for the LCP image often shaves 0.5 to 1.5 seconds on mobile. Google considers an LCP of up to 2.5 seconds good, and often converting the main photo to a modern format is exactly what pulls a page out of the red zone into the green.

CLS (Cumulative Layout Shift) is the shifting of the layout during loading. The image format itself does not affect CLS, but a related habit is important: always set the width and height attributes on the img tag so the browser reserves space in advance. Light AVIF files load faster, the content settles sooner, and there are fewer jumps.

INP and overall responsiveness benefit indirectly: fewer bytes to download means less load on the network and the processor, especially on budget smartphones.

What this gives you for SEO in practice:

• the page enters the green zone of Core Web Vitals, which is a plus for ranking in mobile results;
• a lower bounce rate, because people do not leave a slow page before it loads;
• better indexing, since it is easier for a crawler to get around a lightweight site within its crawl budget;
• higher conversion, since research shows that every extra 100 ms of load time noticeably cuts sales.

One common mistake deserves a separate mention: people add WebP but forget about lazy loading (loading="lazy") for images below the first screen and about fetchpriority="high" for the main LCP image. The format and these attributes work in tandem. And another thing: do not compress to the point where artifacts are visible to the eye, since over-optimization damages trust in a product just as much as slow loading. When you need to fit a specific limit, for example 200 KB for a platform's requirements, it is more convenient to go through targeted compression to that size, and a full set of ready tools lives in our tools hub.

The main question for webmasters is whether the site will break for some visitors. Here are the facts.

WebP is supported by absolutely all current browsers: Chrome, Firefox, Safari (from version 14, that is, since 2020), Edge, Opera, and mobile browsers on Android and iOS. Global coverage exceeds 97 percent of the audience. In practice this means WebP can be served to everyone without a second thought; the risk of meeting a user without support is minimal.

AVIF is younger but also already widely supported: Chrome and Edge since 2020, Firefox since 2021, Safari from version 16 (2022). Global coverage is around 93 to 95 percent and continues to grow. AVIF is not supported only by very old browser versions and some corporate environments stuck on outdated systems.

The correct approach, which removes the compatibility question entirely, is the picture tag with several sources. The browser itself chooses the first format it understands and falls back to JPEG if it supports nothing newer. In terms of logic it works like this:

• first the browser is offered a source with AVIF;
• if it does not understand that, it is offered a source with WebP;
• if it does not understand that either, a regular img with JPEG loads as the fallback.

With this scheme, modern browsers get the lightest format, and old ones see the familiar JPEG and nothing breaks. This is the gold standard, and we recommend exactly this for commercial sites where every percent of the audience matters.

A separate word about platforms and services where you upload photos rather than serve them from your own server. Here things are stricter:

• Amazon, eBay, Etsy and similar marketplaces accept product photos in JPEG and PNG; you cannot upload WebP or AVIF to them. These formats are for your own site, not for a marketplace;
• government portals and official forms also expect JPEG or PNG at a set resolution and weight;
• social media and messengers recompress whatever is uploaded, so serving them AVIF is pointless.

The takeaway is simple: WebP and AVIF are a tool for your own site, landing page or blog. For marketplaces and official portals, keep JPEG of the required size.

There are several ways; we go from the fastest to the most complex and point out the pitfalls right away.

Method 1, an online converter (recommended for most). The fastest path, requiring no software installation and no knowledge of the console. The steps:

• open an online WebP and AVIF converter;
• drag in a photo or a folder of photos;
• choose the format (you can pick both at once) and the quality level;
• download the result and compare the weight with the original.

This takes less than a minute and is suitable when you need to prepare a dozen or two images for an article or landing page. The files are processed right in the browser, and the originals go nowhere.

Method 2, site build tools. If you have a CMS or a static generator, there is usually a plugin or module that serves WebP and AVIF itself and inserts the picture tag. This is the right path for a large site with thousands of images, because conversion happens automatically on upload.

Method 3, the command line. For developers there are utilities such as cwebp and avifenc that run batch conversion via a script. Powerful, but it requires skill and time to set up.

Now the common mistakes we keep running into:

• Converting from an already compressed JPEG. If the source is over-compressed, WebP will only lock in the artifacts, not remove them. Take the highest-quality original you can;
• Quality set too low for the sake of weight. Quality 60 and below produces grit and mush, especially on text and logos. The optimal range for photos is 75 to 85;
• Replacing a PNG with transparency by a JPEG. JPEG cannot do transparency, so the background will turn white. For transparent images, use lossless WebP or AVIF;
• No fallback. You placed only AVIF without the picture tag, and some users see holes instead of images;
• Forgetting about metadata. EXIF adds extra weight and sometimes reveals geolocation. Before publishing, the data is worth cleaning, and there are dedicated EXIF-cleaning tools for that.

When your task is broader than just the format, adjacent tools help: cropping to the right proportions, adding a watermark to protect authorship, and upscaling resolution if the source is too small. For deciding which background to choose for a product card, a dedicated guide covers that too.

An online converter closes 90 percent of tasks: turning a dozen photos into WebP, compressing a banner, preparing images for an article. But there are cases where it is better to hand the work to a professional. First, large catalogs: when you have hundreds or thousands of product photos and need not just conversion but also cutting out the background, aligning to a grid, adding shadows and infographics. Here careful pipeline work without quality loss matters more than the speed of a single click, and a studio can do the background clipping and marketplace infographics in a single style across the whole line. Second, difficult sources: overexposed, murky shots taken on a phone in poor light, which before conversion must be corrected for color and sharpness, otherwise the light format will only lock in the flaws. Third, when you need a stable result at scale and no time to deal with picture tags, fallbacks and quality settings.

To sum up. WebP is lighter than JPEG by about 25 to 35 percent, AVIF by 40 to 50 percent, and both formats are already supported by nearly all browsers. Moving images to modern formats directly improves LCP and other Core Web Vitals, which helps search positions, reduces bounces and raises conversion. For your own site, use picture with the chain AVIF, WebP, JPEG to get both lightness and compatibility. For marketplaces and official portals, keep JPEG of the required weight. Do not chase minimum size at the expense of quality; hold quality in the 75 to 85 range and clean EXIF. And most importantly, do not put it off: you can check the gain right now. Load your photos into a WebP and AVIF converter and in a minute you will see how much lighter your pages become.

Simply converting the images is not enough; it is important to connect them so the site opens for everyone. The modern approach is the picture tag with several sources: the browser itself chooses the lightest format it understands, and if it does not understand a new one, it takes the fallback JPEG. The scheme is simple: first a source with AVIF is specified, then a source with WebP, and at the end a regular img with JPEG as the reliable fallback.

That way a visitor on a fresh browser gets the light AVIF, one on an older browser gets WebP, and one on a very old browser or a rare client sees JPEG and nothing breaks. Do not delete the original JPEGs; they are needed as the fallback. Many engines and plugins can serve WebP automatically, swapping the format on the fly depending on the browser, which is convenient for large sites. The main rule: the new format should speed things up, not break the display of images for part of the audience, so the fallback is mandatory.

WebP and AVIF solve one task but in different ways. WebP is noticeably lighter than JPEG, supported by practically all current browsers and encodes quickly, which makes it a reliable working choice today. AVIF compresses even more strongly, especially on photos with smooth gradients, and gives better quality at a lower weight, but it encodes more slowly and is supported slightly worse in the very oldest browser versions.

The practical choice is this: if you need maximum compatibility and simplicity, take WebP at around 80 percent quality, which already means a saving of thirty to forty percent of weight relative to JPEG with almost no visible difference. If you are chasing top speed and are ready for a slightly more complex setup, add AVIF as the first source at around 50 to 60 percent quality; its quality scale is shifted, and such values give an excellent picture. Ideally, serve both formats through picture, so each browser gets the best it can handle. Do not crank quality down to zero for the sake of weight, or the saving will stop being worth the loss of sharpness.

The new formats are good on your own site, but there are places where they will cause problems. Marketplaces accept product photos in JPEG and PNG and often do not support WebP and AVIF on upload, so prepare cards in JPEG. Government services, documents and most official forms also expect JPEG or PNG. Sending photos to friends in messengers and by email is safer in JPEG, because WebP will not open for everyone.

One more nuance is further editing and printing: not all editors and print shops get along with AVIF, so for those tasks keep the originals in familiar formats. A simple rule: WebP and AVIF are for serving images to visitors of your own site, where you control the connection and the fallback, while everything that goes out to external systems and to people should be served in JPEG or PNG. Then you get both speed where it matters and compatibility where it is critical.

• No fallback JPEG. Images are served only in the new format, and for some visitors they do not load. Always leave a fallback through picture.
• Uploading WebP to a marketplace. The platform does not accept the format, and the card fails. For marketplaces, use only JPEG and PNG.
• Extreme compression. Quality is cranked to the floor for the sake of weight, and artifacts appear. Keep a reasonable balance around 80 percent for WebP.
• Converting from a mushy source. The new format will not improve an already ruined photo; it will only store it more lightly. Convert from a quality original.
• Double compression. An over-compressed JPEG is converted to WebP, layering artifacts on top of artifacts. Start from the highest-quality source.

How much lighter is WebP than JPEG?

At similar quality, WebP is usually 25 to 35 percent lighter than JPEG, and AVIF is lighter still. On a large site this noticeably speeds up loading and improves speed metrics.

Do all browsers open WebP?

Practically all current versions of Chrome, Firefox, Safari and Edge support WebP. AVIF is supported slightly worse in the very oldest versions, so a fallback JPEG is still needed.

Does WebP improve search positions?

The format does not rank directly, but it speeds up the site, and speed is a ranking and usability factor. Fast pages are indexed better and hold on to the visitor.

Can you upload WebP to marketplaces?

No, marketplaces expect JPEG and PNG. Use WebP and AVIF on your own site, and prepare product cards in the supported formats.

For an online store, load speed is direct money: every extra second of waiting lowers conversion and raises bounces, and a mobile visitor on a weak connection simply leaves. Images usually make up the lion's share of a page's weight, so moving the catalog to WebP or AVIF gives the most noticeable speed gain. Lighter images load faster, save the buyer's data and reduce the load on your server, which matters on peak sale days.

This is implemented on the store's own site through automatic serving of WebP with a fallback JPEG, so the images open for everyone. It is important not to confuse things: this is about your own site, not about cards on a marketplace, where photos are still uploaded in JPEG. In other words, the same product is served to visitors of your own store in light WebP for speed, and to marketplaces in JPEG for compatibility. Such a double standard is normal and gives the best of both worlds: a fast site of your own and cards accepted by the platforms.

Setting up WebP is not enough; it is worth making sure the browser actually receives the light version and not the old JPEG. Checking this is simple through the browser's developer tools. Open the page, press F12, go to the Network tab, refresh the page and look at the loaded images: the type column or the file name should say webp or avif, not jpeg. If it still says JPEG, then the format swap is not working and the setup needs fixing.

A second reference point is the file size in the same tab: the WebP version should weigh noticeably less than the original JPEG. It is also useful to run the page through speed-testing services; they will point out directly if images can be served in a more modern format and will show the potential saving. Check across different browsers, because serving depends on support, and be sure to confirm that on a browser without support for the new format the fallback JPEG loads correctly. Such a check takes a couple of minutes and guarantees that all the conversion work really speeds up the site rather than lying as dead weight.

The new formats can do more than just compress photos lightly, and this widens their use. Both WebP and AVIF support transparency the same way PNG does, so a logo or an image with a transparent background can be served in WebP and get both transparency and small weight at once, which cannot be achieved with JPEG. For sites this means that even graphics with transparent areas, which used to be kept in a heavy PNG, can now be lightened while preserving clean edges and a backdrop that works over any background.

WebP can also do animation, acting as a lighter replacement for the outdated GIF format: an animated WebP weighs many times less at better quality and smoothness. This is useful for small animated banners and icons on a site. At the same time it is important to remember the fallback: where part of the audience may be on an old browser, a fallback is still kept for animation and transparency, whether it is PNG for static images or another supported format. Overall, the combination of small weight, transparency and animation in one format makes WebP a universal tool for web graphics, and AVIF adds even stronger photo compression on top of that.

A mass switch to WebP and AVIF should be done carefully so as not to break the display of images for some visitors. Start small: take one page template or one section, set up serving of WebP with a fallback JPEG, and confirm through the browser tools that the light version really loads and that on an old browser the JPEG is correctly substituted. Only once you are sure everything works should you roll the approach out to the whole site. Keep the original JPEGs; they are needed as a fallback and as a base if you ever need to regenerate images in another format or size.

On a large site, manually converting each image is unrealistic, so a module or plugin is usually connected that creates WebP versions automatically and serves them to supporting browsers, leaving JPEG for the rest. This removes the manual work and makes the switch transparent for content managers, who keep uploading the familiar JPEGs. After implementation, run the key pages through speed-testing services and confirm that image weight has dropped and load metrics have improved. A step-by-step switch with a mandatory fallback format gives you all the speed benefit without the risk that images vanish for any of your visitors.

Is converting to AVIF free?

Yes, converting a photo to AVIF online is completely free; no registration or software installation is needed, you simply upload a file and download the finished AVIF.

Which formats can I convert from?

An AVIF converter typically accepts JPG, PNG and WebP and saves the result in AVIF, so you can compress even already optimized WebP images by roughly another 30 percent.

What happens to my uploaded photos?

With a good tool, an uploaded photo is processed only to create the AVIF and is deleted automatically; reputable services do not publish or hand your images to third parties.

Does AVIF reduce quality?

AVIF gives the same visual level as WebP but at a lower weight, so the shot stays sharp while the file becomes lighter for a faster-loading site.

Does AVIF work on mobile?

AVIF is supported by all modern browsers on iPhone and Android, and a browser-based converter works right in the mobile browser without any apps.