What is a WebP file? How to open it and turn it into a JPG

The short version

• A WebP (.webp) is a compressed picture, like a JPG, made by Google to be smaller.
• It opens in any current browser: Chrome, Edge, Firefox, Opera and Safari. On Apple devices that means Safari 14 or later, which needs iOS 14 or macOS Big Sur or later.
• It saved as WebP because the website sent WebP, which websites do when your browser can show it.
• Accepted by: Google Search (pictures on your website), Google Merchant Center (on its list of supported formats) and eBay.
• Google Business Profile: Google’s photo guidelines say JPG or PNG. Use a JPG.
• Converting to JPG? Open it and export or save it as JPEG; don’t just rename it. Start from the original if you have it: on our images, a JPG made from the WebP was further from the original every time.
• Is it really smaller? Usually. Matched for quality on SSIM, the measure Google uses, our 60 WebPs were about 32% smaller than JPG in total, but 5 of the 60 came out bigger. Google’s own figure is 25 to 34%. On a different measure we got about 48%, close to what our earlier posts said.

What is a WebP file?

It is a picture format, made by Google. Google’s WebP page describes it like this: "WebP is a modern image format that provides superior lossless and lossy compression for images on the web." Lossy means it throws away detail you are unlikely to notice, as a JPG does. Lossless means it keeps every pixel, as a PNG does. A WebP can be either, and Google says both kinds can have a transparent background, as a PNG can.

Mozilla’s guide to image formats explains where the lossy kind comes from: "WebP supports lossy compression via predictive coding based on the VP8 video codec". VP8 is a way of compressing video, and WebP uses it on a single still picture. The AVIF files we wrote about last week do the same thing with a newer video codec.

Google’s own claims for the format are specific: "WebP lossy images are 25-34% smaller than comparable JPEG images at equivalent SSIM quality index", and "WebP lossless images are 26% smaller in size compared to PNGs." Those are its maker’s figures. Our own test is further down.

Why did my picture save as WebP?

When you save a picture from a website, you get the file the website sent to your browser, and many websites now send WebP. Google’s WebP FAQ explains how they decide. Browsers commonly tell a website in advance which formats they accept, and once a browser says it accepts WebP, "the web server knows it can safely send WebP images". Google’s advice to website owners is to "serve WebP images only to clients that can display them properly" and fall back to older formats for the rest.

So nothing on your computer has changed. The website gave your browser a WebP because your browser can show one, and saving the picture kept the format it arrived in.

How to open a WebP file

Open it with your web browser. Google’s FAQ lists WebP support in Chrome, Edge, Firefox and Opera, and in Android’s own browser since Android 4.0. For Apple devices it gives "Safari 14+ (iOS 14+, macOS Big Sur+)". Apple’s Safari 14 release notes put it in four words: "Added WebP image support." On a Mac the operating system matters as well as the browser. Mozilla’s guide says: "You need Safari 14 or later as well as macOS Big Sur (11) or a more recent version."

That is more use than some of what ranks for this question. One of the guides on the first page of results when we searched, from a seller of Shopify themes and dated April 2025, says only that "Safari has added support as well, but certain outdated versions of browsers could be a problem." Google’s list tells you which versions.

On Windows, Microsoft publishes a free WebP Image Extension in the Microsoft Store, which it says "will enable you to view WebP images in the Windows File Explorer, Photos and other Windows apps." We haven’t checked which versions of Windows come with it already, and we haven’t tested it, so if Photos won’t open a WebP, the browser is the simpler route.

How to turn a WebP into a JPG

First, go back to the original if you have it. Every time a picture is compressed, a little more of it is lost. We measured this: for each of our 60 test images, we made a JPG from the WebP and another JPG straight from the original, at the same setting. The JPG made from the WebP was further from the original on all 60. Using PSNR, a standard measure of how far a compressed picture has drifted from the original (higher is closer), the typical JPG scored 41.6 made from the original and 39.8 made from the WebP. We found the same with HEIC and AVIF. If the WebP is all you have, convert it once and keep the JPG.

• On a Mac: Apple’s Preview guide says: "Open the file you want to convert, then choose File > Export." Then: "Click the Format pop-up menu, then choose HEIC, JPEG, JPEG-2000, OpenEXR, PDF, PNG or TIFF." Choose JPEG. Apple’s page doesn’t say whether Preview opens WebP, and we haven’t tested it.
• On Windows: open the picture in Paint and save it as a JPEG. Microsoft’s Paint page says "you can save your work in various file formats, including PNG, JPEG, BMP and GIF, among others". If Paint won’t open the WebP, the extension above may be what’s missing. We haven’t tested Paint with a WebP.
• Online converters: there are plenty, and some of the guides that rank for this question come from companies with a converter of their own. We haven’t tested any. Using one means uploading your picture to someone else’s server, which is fine for a product photo but worth a thought for anything private.
• Don’t just rename it. Changing .webp to .jpg leaves a WebP inside. Merchant Center’s image rules say "The image's file extension should correspond to its format", and warn that a wrong one "can lead to 'Unsupported image type' errors".

Where you can use a WebP, and where you can’t

This is the part that matters if you sell things or run a website. We read each of these pages on 21 and 23 October 2026.

WebP is welcome in more places than its reputation suggests. Merchant Center, which feeds Google Shopping and the free product listings, lists it among its supported formats, straight after JPEG. When we first read that page, on 21 October 2026, JPEG and WebP were both marked "recommended". By the morning we published, 23 October, Google had rewritten the page and the label had gone from both, so we no longer say it. WebP is still on the list. eBay takes it, and so does Google Search for the pictures on your website. Merchant Center has size rules too, which we covered in Google’s 500 × 500 image rule.

Business Profile is the exception, and it is a soft one. Google introduces its list with "Your photos look best on Google if they meet the following standards", which reads like guidance rather than a list of what the upload will refuse. We haven’t tried uploading a WebP to a Business Profile, so we can’t tell you it would be rejected. Google names JPG first, so use a JPG.

Should your website use WebP?

If your website builder handles it, probably yes. Google Search takes it, every current browser shows it, and the files are usually smaller. Google’s pitch is that smaller images “make the web faster”.

We have tested how much smaller on our own pictures. On 3 October we saved all 60 share images from this blog as JPG and as WebP, for our post JPG or PNG? On 13 October we refined the test for the AVIF post, matching each WebP to its JPG’s quality picture by picture. For this post we matched them a second way, on SSIM, which is meant to track what people notice and is the measure Google’s 25 to 34% claim uses.

Matched on PSNR, WebP was smaller on all 60 pictures, and about 48% smaller in total. Matched on SSIM, it was smaller on 55 of the 60 and about 32% smaller in total; on the other 5, the WebP had to be bigger than the JPG to score as well, by up to about 21%. The gap between the two answers comes from a small disagreement. The WebPs matched on PSNR scored slightly below their JPGs on SSIM (typical score 0.975 against 0.978), and closing that small gap cost a third of the saving. The SSIM figure is the fair one to set beside Google’s, and it lands inside Google’s 25 to 34%.

That changes what we told you before. Our JPG or PNG? post gave about 45% and our AVIF post about 48%, both judged on PSNR. The AVIF post said that matching on PSNR “flatters WebP slightly”. On SSIM it flatters WebP by a third of the saving, which is not slight. Both posts now carry a dated note pointing here.

Mozilla’s guide gives a similar range to Google’s: "Lossy WebP images are on average 25–35% smaller than JPEG images of visually similar compression levels." It also gives the advice that matters most for website owners: "Provide a fallback in either JPEG or PNG format, such as with the <picture> element." That is a job for whoever builds your site, not something to do by hand.

What argues the other way

• Our test is small and particular. Our 60 pictures were generated by AI and are smooth and clean. Busy, grainy photos may compress differently. We used one piece of software (Pillow, a widely used image library) at its slowest, most thorough WebP setting, and one JPG setting (quality 85).
• The measure changes the answer. The same 60 pictures gave about 48% on one measure of quality and about 32% on another. Neither measure is simply right, and a figure quoted without its measure, ours included, tells you less than it seems to.
• Google’s figures are its maker’s. Google created WebP and publishes the comparison. That doesn’t make the figures wrong, and Mozilla’s are close, but neither is an independent test of your pictures.
• Older devices won’t show it. An iPhone that can’t run iOS 14, or a Mac that can’t run Big Sur, won’t show a WebP in Safari. That is why the fallback advice above exists.
• For anything you send elsewhere, JPG is still the safe default. We keep our own share images as JPGs for that reason: they get posted to places whose rules we haven’t all checked.

Sources

• Google: An image format for the Web (last updated 7 August 2025) and Frequently Asked Questions (last updated 3 February 2026), for what WebP is, Google’s size claims, the browser list and how websites decide to send WebP.
• Mozilla (MDN): Image file type and format guide, for the VP8 origin, Mozilla’s size range, the macOS requirement and the fallback advice. Apple: Safari 14 Release Notes.
• Google: Image SEO Best Practices (last updated 2 March 2026), Image link [image_link] (Merchant Center Help) and Manage your Business Profile photos and videos. eBay UK: Adding pictures to your listings.
• Microsoft: WebP Image Extension (Microsoft Store, published by Microsoft, listed as free) and Draw, Create and Edit with Paint. Apple: Convert image file types using Preview on Mac.
• The page-one guide we quote: debutify.com, dated 23 April 2025.
• All of the pages above were read on 21 October 2026, and again on 23 October 2026, the morning we published. Only Google’s Merchant Center page had changed in what we quote: it no longer marks any format “recommended”, and its line on file extensions now says “should” where it said “must”. The post quotes the new version.
• Our test: the same 60 share images (1,200 × 630 pixels, saved as PNG) as our 3 October test, with Pillow 12.2.0. JPG at quality 85 with optimisation on; WebP at its slowest setting (method 6). PSNR was measured on the full colour picture; SSIM with ffmpeg. "Matched" means the smallest WebP that scored at least as well as that picture’s JPG on the measure named, found by searching WebP’s quality settings from 1 to 100. The PSNR-matched files are the ones from our 13 October AVIF test, and the WebP-to-JPG test started from those; the SSIM matching and the WebP-to-JPG test were run on 21 October 2026. Our 3 October post gave about 45%, comparing both formats at the same quality number rather than matching them. KB and MB mean thousands and millions of bytes.
• Every quotation above was tested automatically against the text of its source before publication.