Saved a picture and ended up with a .webp file nothing wants to open? Here is what the format actually is, how to view it on every major device, when JPG or PNG is the better target, and how it stacks up against JPEG and PNG.
What is WebP? It is an image format Google introduced in 2010 to make the pictures on web pages lighter. A WebP file can be lossy or lossless, can carry a transparent background and even animation, and a lossy one is typically 25–34% smaller than a JPEG of comparable quality. Current browsers, Windows 10 and 11, macOS Big Sur and later, Android, and iOS 14 or newer all open it natively. When an older program or an upload form refuses the file, converting it to JPG or PNG takes a few seconds and solves the problem for good.
For the conversion itself, use WebP to JPG for photographs and WebP to PNG for logos, icons, stickers and anything with a transparent background. Going the other way, JPG to WebP and PNG to WebP will lighten the images on your own site. The rest of this guide explains where these files come from, how to open them on each platform, and how to decide on the right target format.
Most people meet the format by accident. You right-click a picture on a news site or a shop, choose “Save image as”, and the download arrives as product-shot.webp. Double-click it and an older viewer complains that the file type is not supported. Nothing went wrong on your side. With every request, your browser tells the server which image formats it understands, and a server that sees WebP on that list sends the lighter version. The page loads faster, the site pays for less bandwidth, and you end up holding a file your desktop software may not recognize.
So the file is neither corrupt nor dangerous; it is simply younger than JPEG and PNG. Trouble only starts outside the browser, where older desktop programs, previous generations of office software and a surprising number of upload portals still do not know what to do with it.
Technically, a .webp file is image data wrapped in a RIFF container. Lossy mode borrows the intra-frame (keyframe) compression of the VP8 video codec, while lossless mode is a separate algorithm designed specifically for stills. The format stores 8 bits per channel, supports an alpha channel for transparency, and can hold multi-frame animation. Each side of an image is capped at 16,383 pixels, which never matters for phone photos but can bite with very wide panoramas.
One more detail explains a common complaint. In lossy mode, color is stored at half the resolution of brightness, a scheme called 4:2:0 chroma subsampling. Photographs hide this perfectly, but thin red lettering on a blue background, or similar hard color edges, can come out slightly soft.
Nothing in the file name tells you whether an image was saved lossy or lossless. That has a practical consequence: turning a lossy file into PNG does not bring back the discarded detail. PNG only guarantees that no further loss happens from that moment on. If you still have the original JPG or PNG, edit that instead.
The universal shortcut is to drag the file into any up-to-date browser window. Current versions of Chrome, Edge, Firefox and Safari display it immediately. For a permanent fix, follow the steps for your operating system below.
On macOS Big Sur (11) and later, Preview opens the format, and selecting the file in Finder and pressing the space bar shows it in Quick Look. Preview also hides a handy converter: choose File > Export and set the format to JPEG or PNG. On an older macOS release, open the image in a browser or convert it first.
Android has decoded the format natively for many years, so gallery apps show these images without fuss. On iPhone and iPad, iOS 14 and later display them in Photos. On a phone the real friction is sharing rather than viewing: some apps and web forms reject a .webp picked from the camera roll, and the only reliable workaround is converting before you upload. A small piece of trivia: the stickers in several messaging apps are themselves transparent WebP files.
The format causes the most friction outside the browser. Older image editors, print-shop upload pages, internal company dashboards and application forms that say “JPG, JPEG or PNG only” turn these files away. The typical symptoms are messages such as “This file type is not supported” or “Invalid file format”, or a file picker that greys the image out entirely. At that point the only lasting fix is a real conversion.
The classic shortcut is renaming photo.webp to photo.jpg. That changes the label, not the contents. A few programs sniff the data and open it anyway, but any system that checks the actual file type will still reject it, and our own converters refuse files whose contents do not match their extension.
What is in the picture decides the target, not personal taste:
product-shot.jpg.Each upload is processed on the server within that request and returned in the response; nothing is stored or shared, and there is no account or fee.
Going from WebP to JPG means saving lossy data as lossy once more, but at quality 90 that second pass is invisible at normal viewing distance. What surprises people is the size: a 180 KB original can easily become a 250–300 KB JPG. That is not a bug, just JPEG being less efficient at storing the same picture. Converting a photo to PNG inflates it several times over, because PNG throws nothing away. If weight matters, run the result through the image compressor and settle on a quality between 75 and 82.
Lined up side by side, the three formats show why the newcomer took over the web and why the two veterans refuse to retire.
| Property | WebP | JPEG | PNG |
|---|---|---|---|
| Compression | Lossy and lossless | Lossy only | Lossless only |
| Transparency | Yes | No | Yes |
| Animation | Yes | No | Only via the APNG extension |
| Bit depth | 8 bits per channel | 8 bits in practice | 8 or 16 bits |
| Typical photo weight | 25–34% below JPEG | Baseline | Often several times larger |
| Largest side | 16,383 px | 65,535 px | Effectively unlimited |
| Compatibility | Modern browsers and systems | Virtually all software | Almost every program |
The size figures come from comparisons Google has published: lossy WebP typically lands 25–34% below JPEG at equivalent visual quality, and lossless WebP about 26% below PNG. Your own results will drift with content. Smooth gradients such as sky and skin tend to widen the gap, while small images that were already well compressed narrow it.
Bumping into the format as a visitor can be annoying, but as a site owner it works in your favour. A product photo 1600 pixels wide that weighs 400 KB as a JPG typically drops into the 260–300 KB range after conversion. Multiply that by twenty images on a category page and the difference is obvious on a mobile connection.
The file is an image, not a program, so opening one does not install anything by itself. Like every image decoder, though, the WebP library has had security bugs; the serious one tracked as CVE-2023-4863 in libwebp was fixed in 2023 through browser and system updates. Keeping your browser and operating system current is the sensible precaution.
No. The name changes and the contents stay the same. Turning the file into a real JPG requires re-encoding it, which is a conversion that takes seconds.
Sites send it because your browser announced support for it. The same address may deliver a JPG to a different browser or an older app. Saving the file and converting it afterwards is the easiest route.
AVIF usually produces smaller files at the same quality, but it encodes more slowly and older software supports it less well. WebP wins on compatibility and speed, AVIF on raw file size.
To keep going, read what is AVIF for the next-generation alternative, our PNG vs JPG comparison for the two classics, the step-by-step guide on how to reduce image file size for forms and email, and how to choose an image format for all four formats in one table.
