WebP

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WebP is a raster image format developed by Google for delivering images on the web. It supports lossy and lossless compression, transparency, and animation. Files use the .webp extension and the image/webp MIME type.

WebP can often produce a smaller file than JPEG, PNG, or GIF while maintaining comparable visual quality. This can reduce bandwidth usage and help a page load faster. However, using WebP alone does not guarantee strong website performance. Image dimensions, compression settings, responsive variants, markup, and loading priority still matter.

What does WebP mean?

WebP is the name of an image format designed primarily for use on the web. Google introduced it in 2010 as a way to reduce the size of images transmitted over the internet.

WebP combines capabilities commonly associated with several older formats:

lossy compression similar to the approach used by JPEG;
lossless compression and transparency associated with PNG;
multi-frame animation similar to GIF;
support for color profiles and selected metadata.

This does not mean WebP is always the best replacement for every other format. The right choice depends on the type of image, required quality, software compatibility, and actual compression results.

How does WebP work?

WebP reduces file size by analyzing image data and encoding it more efficiently. The exact process depends on whether lossy or lossless compression is selected.

Lossy compression simplifies or discards some information. The encoder attempts to remove data whose loss will be least noticeable to the viewer. Stronger compression can produce a smaller file, but it may also introduce blurred details, blocking, halos, or inaccurate color transitions.

Lossless WebP preserves the image data without compression-related information loss when the file is decoded. It is generally larger than a lossy WebP file, but it may still be smaller than an equivalent PNG.

Lossy WebP

Lossy WebP is commonly used for:

photographs;
product images;
color-rich banners;
background images;
article thumbnails;
graphics where minor detail loss will not be noticeable.

The quality level can be adjusted during export. A lower quality setting usually reduces file size but increases the likelihood of visible artifacts. The value shown by an image tool is not the percentage of quality retained, and different encoders may produce different results at the same numerical setting.

Lossless WebP

Lossless WebP may be suitable for graphics where sharp edges, solid areas, text, or transparency are important. Potential uses include:

screenshots;
interface elements;
charts and raster illustrations;
graphics with transparent backgrounds;
images whose pixel data must be preserved.

The result should still be compared with PNG. Depending on the image, encoder, and settings, the difference may be small, and another format may occasionally produce a better result.

Does WebP support transparency?

Yes. WebP supports an alpha channel, allowing images to contain fully or partially transparent areas. Transparency can be used with both lossy and lossless WebP images.

This makes WebP a possible alternative to PNG for background-free product images, decorative elements, shadows, overlays, and other graphics displayed over changing page backgrounds.

Before replacing PNG, inspect the edges of the subject on both light and dark backgrounds. Excessive compression may create halos, remove fine details, or change the appearance of semitransparent areas.

Can WebP be animated?

WebP can store an animation made of multiple frames. Unlike traditional GIF, it supports a much broader color range, partial transparency, and both lossy and lossless compression.

An animated WebP may be smaller than an equivalent GIF, but it is not always the best option. Video formats may be more efficient for long sequences, large frame sizes, or content that needs playback controls.

Animation should not be used purely as decoration when it distracts users, interferes with reading, or may cause discomfort. A website should also account for the user’s reduced-motion preference.

WebP vs. JPEG

JPEG, also known as JPG, is a widely used photographic format based on lossy compression. WebP can produce a smaller file at comparable visual quality while also supporting transparency and animation.

Google reports that lossy WebP images in its tests were approximately 25-34% smaller than comparable JPEG images at equivalent quality under the study’s measurement method. This is not a guaranteed result for every file. The actual difference depends on the photograph, resolution, compression settings, and encoder.

JPEG can still be useful as a source format, a fallback for older systems, or a file exchanged with software that does not support WebP. Repeatedly converting an already compressed JPEG into additional lossy formats should be avoided because each operation can reduce image quality.

WebP vs. PNG

PNG supports lossless compression and transparency. It is commonly used for screenshots, interface graphics, illustrations, and images with alpha transparency.

According to Google, lossless WebP files can be approximately 26% smaller than comparable PNG files on average. A specific image may produce a different result. A simple, well-optimized PNG may not become significantly smaller after conversion.

PNG can also be a better working or archival file because it is widely supported by graphics software and does not require lossy compression. A WebP version can then be generated specifically for website delivery.

WebP vs. GIF

GIF is best known for simple animations, but it has a limited color palette and generally does not provide compression as efficient as newer alternatives.

Animated WebP can offer:

more colors;
partial transparency;
lossy or lossless compression;
a smaller file for a comparable animation;
better detail and smoother color transitions.

If the content resembles a video clip, WebP should also be compared with MP4 or WebM. A video format may provide more efficient compression and greater control over playback.

WebP vs. SVG

WebP is a raster format, meaning it stores an image as a grid of pixels. Enlarging it beyond its original resolution can make it appear soft or pixelated.

SVG is a vector format. It is generally a better choice for logos, icons, diagrams, simple illustrations, and elements that must remain sharp at every size.

Converting a simple logo from SVG to WebP can remove its most important advantage: lossless scaling. WebP should primarily be used for raster content such as photographs and complex images.

WebP vs. AVIF

AVIF is a newer image format that can provide more efficient compression than WebP for many images. It supports lossy and lossless compression, transparency, animation, and broader color capabilities.

That does not make AVIF universally better. Depending on the image and tool, encoding may take longer, and aggressive compression can remove important detail. WebP remains a practical and widely supported option, especially in established workflows involving WordPress, graphics tools, and content delivery networks.

A website can provide several formats for the same image. The browser will select the first supported source listed in a picture element, such as AVIF first, WebP second, and JPEG as the final fallback.

Main benefits of WebP

often smaller files than comparable JPEG or PNG images;
support for lossy and lossless compression;
support for transparency;
support for animation;
native support in current versions of all major browsers;
the ability to use WebP in a regular img element;
support from Google Search and Google Images;
support in WordPress and many other content management systems;
reduced bandwidth usage;
the potential to improve page loading performance.

WebP limitations

not every image becomes significantly smaller after conversion;
excessive compression can visibly reduce image quality;
older software, browsers, and systems may not support the format;
conversion may remove or change metadata;
WebP does not replace SVG for vector graphics;
the format does not solve the problem of oversized image dimensions;
sending one large file to every device still wastes bandwidth;
an incorrectly configured server may return the wrong MIME type;
automatic optimization can produce images with insufficient quality;
keeping both originals and generated variants can increase server storage usage.

Do all browsers support WebP?

WebP is natively supported by current versions of major browsers, including Chrome, Edge, Firefox, Safari, and Opera. Compatibility problems are most likely to affect very old browsers, outdated operating systems, legacy applications with embedded web views, and certain external systems.

If a website must support those environments, a picture element can provide a JPEG or PNG fallback. The browser will automatically choose the first format it can display.

How do you use a WebP image in HTML?

Current browsers can load a WebP file directly from an img element:

<img
    src="/images/product.webp"
    alt="Black electric fireplace in a modern living room"
    width="1200"
    height="800">

The width and height attributes help the browser reserve space before the image downloads, reducing layout shifts. Alternative text should describe the image’s meaning rather than its file format.

How do you provide a fallback format?

The picture element can provide multiple formats for the same image:

<picture>
    <source srcset="/images/product.avif" type="image/avif">
    <source srcset="/images/product.webp" type="image/webp">
    <img
        src="/images/product.jpg"
        alt="Black electric fireplace in a modern living room"
        width="1200"
        height="800">
</picture>

The browser evaluates the sources in order. If it supports AVIF, it downloads the first file. Otherwise, it may choose WebP and ultimately fall back to the JPEG specified by the img element.

A fallback is not always necessary. Direct WebP delivery may be sufficient when the website only supports current browsers.

WebP and responsive images

Changing the file format does not replace the need to match image dimensions to the user’s device. An image displayed in a 400-pixel-wide area should not unnecessarily contain several thousand pixels of width.

The srcset and sizes attributes allow the browser to choose from several image dimensions:

<img
    src="/images/product-1200.webp"
    srcset="
        /images/product-480.webp 480w,
        /images/product-800.webp 800w,
        /images/product-1200.webp 1200w"
    sizes="(max-width: 767px) 100vw, 800px"
    alt="Black electric fireplace in a modern living room"
    width="1200"
    height="800">

The strongest results come from combining an efficient format, appropriate compression, and dimensions matched to the image’s rendered size.

WebP in WordPress

WordPress has supported uploading and using WebP files since version 5.8. Images can be added to the Media Library and placed in content much like JPEG or PNG files, provided the server and its image-processing libraries support the format.

Native WebP support does not mean WordPress automatically converts every uploaded JPEG and PNG. Automatic generation and delivery of WebP variants may be handled through:

an image optimization plugin;
a content delivery network;
hosting configuration;
WordPress filters and custom code;
an export process used before upload;
build tools used during website development.

Before optimizing an existing Media Library, create a backup and confirm that the system updates URLs correctly, generates all required image sizes, clears cached files, and allows the original images to be restored.

Does WebP improve SEO?

WebP does not automatically improve search rankings. Google supports and can index WebP images, but the format itself does not guarantee better organic visibility.

A smaller image may download faster and improve overall page performance. This can indirectly support user experience and Core Web Vitals results. The outcome depends on the complete implementation rather than the file extension alone.

Image SEO still requires:

accurate and useful alternative text;
a descriptive filename;
a file extension that matches the actual format;
appropriate image dimensions;
responsive variants;
correct use of the img element;
images that search engine crawlers can access;
high-quality visuals relevant to the page content.

WebP and Core Web Vitals

An image may be the largest element visible when a page first opens and determine its Largest Contentful Paint, or LCP, result. Reducing the file size may shorten the download and help the page display its primary content sooner.

WebP does not fix every LCP problem. A poor result may still be caused by:

oversized image dimensions;
late discovery by the browser;
low loading priority;
a slow server response;
delivering the image as a CSS background;
render-blocking stylesheets or scripts;
lazy-loading the primary image unnecessarily;
missing or unsuitable srcset variants.

Images below the initial viewport can generally be lazy-loaded. The primary LCP image should be discoverable early and should not usually use loading="lazy".

How do you convert an image to WebP?

WebP files can be created with:

graphics applications that support WebP export;
online conversion tools;
Google’s cwebp utility;
CMS optimization plugins;
website build tools;
a server or CDN that generates image variants on demand.

A basic cwebp command may look like this:

cwebp -q 80 input.jpg -o output.webp

The value 80 is a quality setting, not a statement that the file retains exactly 80% of the original quality. The output should be inspected visually and compared with the source file’s size.

What WebP quality setting should you use?

There is no single correct setting for every image. A product photograph, blurred background, screenshot, and text-based graphic require different parameters.

When selecting a quality level:

begin with a setting that maintains high visual quality;
increase compression gradually;
inspect the image at its actual rendered size;
check faces, textures, gradients, and sharp edges;
compare WebP with an optimized JPEG, PNG, or AVIF file;
test the image on high-density displays;
do not keep a larger file simply because it uses a newer extension.

If the WebP file is larger than a well-optimized original or the difference is negligible, using it may provide no meaningful benefit.

Can the original files be deleted after conversion?

It is generally worth preserving the source image outside the directory used for public delivery. The source can later be used to generate a different size, quality level, or newer format.

A delivery-ready WebP file is not always a suitable working master. Reprocessing an already compressed file may reduce quality, especially when lossy compression was used.

Deleting originals from a live website’s Media Library also requires caution. They may be used as fallbacks, downloadable attachments, thumbnail sources, or assets referenced in the CMS database.

Can you rename a JPG file to WebP?

No. Changing a filename from image.jpg to image.webp does not convert the data stored inside it. The browser or server may then detect a format that does not match the extension, causing display errors and an incorrect MIME type.

The image must be processed by a tool that actually encodes its data as WebP.

Common WebP implementation mistakes

converting images automatically without inspecting their quality;
treating a quality setting as the percentage of data retained;
delivering the same large image to mobile and desktop devices;
omitting width and height attributes;
lazy-loading the main LCP image;
replacing scalable SVG files with raster images;
keeping a larger WebP file when it provides no benefit;
repeatedly encoding lossy images;
deleting originals without a backup;
failing to review metadata and color profiles;
returning the wrong MIME type from the server;
failing to clear caches after changing formats;
assuming a modern format replaces complete performance optimization.

When should WebP be used?

WebP is a strong choice when:

you publish photographs and raster graphics on a website;
you want to reduce transferred data;
you need a raster image with transparency;
you support current browsers;
your CMS, server, or CDN processes the format correctly;
conversion produces a smaller file at acceptable quality;
you can generate multiple sizes for different screens.

Another format may be better when you need a scalable vector graphic, an editable master file, maximum compatibility with legacy software, or when an optimized JPEG, PNG, or AVIF produces a better result.

Key facts about WebP

WebP is a raster image format developed by Google;
files use the .webp extension and the image/webp MIME type;
the format supports lossy and lossless compression;
it can store transparency and animation;
it often produces smaller files than JPEG, PNG, or GIF;
a smaller file is not guaranteed for every image;
WebP is supported by current versions of all major browsers;
Google can index images stored in the format;
WordPress has supported WebP since version 5.8;
the format does not replace responsive sizing and appropriate compression;
WebP does not automatically improve SEO or Core Web Vitals;
quality and file size should be evaluated for every image;
the original source file should be preserved for future processing.

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