You right-clicked an image on a website, saved it, and got a file ending in .webp. Now Photoshop will not open it, the print shop rejected it, and the form you are uploading to says the format is unsupported.
What WebP is
WebP is an image format Google introduced in 2010 to replace both JPEG and PNG. It genuinely is better: roughly 25-35% smaller than JPEG at the same visual quality, with support for transparency and animation. Which is why it has spread — most websites now serve WebP to browsers that accept it, which is all of them.
The problem is everything that is not a browser. Older versions of Photoshop, many print workflows, a lot of upload validators and plenty of desktop software still do not accept it. So you end up with a file that displays perfectly in Chrome and is useless everywhere else.
Converting it
It runs in your browser, so nothing is uploaded.
JPG or PNG?
Pick based on what the image contains, not on habit:
JPG if it is a photograph. Smaller files, universal support, and the lossy compression is invisible on photographic content.
PNG if the image has transparency, or contains text, or is a logo, screenshot or illustration with flat colour areas. PNG is lossless, so no artefacts, at the cost of a larger file.
The transparency point matters. WebP supports transparency; JPG does not. Convert a transparent WebP to JPG and the transparent areas become white. If your logo needs to sit on a coloured background, convert to PNG.
Avoiding the conversion entirely
If you keep hitting this, the download step is usually where it starts.
Right-click and "Open image in new tab" first, then save. Sometimes the site serves a JPG at the direct URL and only converts to WebP for the page.
Try removing WebP parameters from the URL. Many CDNs use a query string like "?format=webp" or a path segment like "/webp/". Loading the URL without it often returns the original.
Take a screenshot instead for anything you only need visually. Lower quality, but instant and always in a usable format.
Check whether you can just install support. Windows 11 handles WebP natively in Photos. Recent Photoshop opens it. If your software is a few versions behind, updating may remove the problem permanently.
Quality when converting
A WebP is already lossily compressed. Converting to JPG re-encodes it, which is a second lossy pass, so there is some quality loss stacked on top.
In practice this is not visible for normal use. Where it does show:
Text and sharp edges pick up visible artefacts fastest. Convert those to PNG instead.
Images destined for print should keep as much quality as possible — convert to PNG, which is lossless and avoids the second lossy pass entirely.
Repeated round trips — WebP to JPG to WebP to JPG — degrade noticeably. Keep an original in one format and convert from it each time rather than converting a converted file.
Going the other way
If you are building a website, the conversion you want is usually the reverse: JPG and PNG into WebP, for the file-size savings. The same converter handles that direction. Cutting your image weight by a third is one of the cheapest page-speed improvements available, and every browser in current use supports it.