What is a WebP file?
You right-clicked an image, chose “Save image as”, and ended up with a file ending in .webp.
Windows Photo Viewer will not open it. Word will not insert it. The upload form on the site you
needed it for rejects it outright.
You have not done anything wrong. Here is what happened.
WebP is what the website actually sent you
When your browser requests an image, it tells the server which formats it can handle. Chrome, Edge, Firefox and Safari all advertise WebP support, so a server configured for performance sends WebP rather than JPG — a file typically 25 to 35 per cent smaller for the same visual quality.
“Save image as” saves what was received. It does not convert anything. So you get the WebP.
Confusingly, the save dialog sometimes suggests a .jpg filename anyway. Accepting it gives you a
file named .jpg that contains WebP data, which is worse than the original problem: the extension
now lies about the contents, and software fails in more baffling ways.
Why WebP is good, and why it keeps annoying you
WebP does genuinely useful things. It has lossy and lossless modes, supports transparency in both (unlike JPG), handles animation (unlike PNG), and cuts image weight substantially. For a website owner watching Core Web Vitals, that is a real improvement.
The trouble is the gap between browsers and everything else. Browsers adopted WebP years ago. The rest of the software world — Windows Photo Viewer, older Office versions, print shops, photo kiosks, countless upload forms with hard-coded extension checks — did not. So the format is simultaneously excellent on the web and a nuisance the moment a file leaves the browser.
What to do with a WebP file
If you just need to view it: open it in your browser. Drag the file onto any browser window and it will display.
If you need to use it elsewhere: convert it. WebP to JPG is the right choice for photographs and for anything an upload form will accept. WebP to PNG is the right choice if the image has a transparent background, because JPG cannot store transparency and will fill it with white.
If it needs to go into a document or a print job: JPG for photographs, PNG for logos and screenshots. Neither will surprise anyone downstream.
How to stop getting WebP files
There is no clean switch to flip. A few practical options:
- Screenshot instead. Cropping a screenshot gives you a PNG. Quality is limited to your screen resolution, but for many purposes that is fine.
- Try the URL. Some sites keep the original JPG at the same path with a different extension. Worth thirty seconds if the image matters.
- Convert on the way through. A converter that runs locally adds a couple of seconds and gives you a file that works everywhere.
Browser extensions that force JPG delivery exist, but they work by lying about what your browser supports, which makes every image you load larger and slower. Converting the occasional file you actually save is a better trade.
Should you use WebP on your own website?
Yes — with a fallback. Serve WebP to browsers that accept it and JPG to those that do not, using the
<picture> element or your CDN’s automatic format negotiation. Almost every static host and image
CDN does this for you now.
What you should not do is upload WebP files to places where humans will download them. If you are attaching images to an email, a shared drive, or a document other people will open, send JPG or PNG. The bandwidth you save is not worth the support conversation.