WebP to JPG: When to Convert, When Not To, and Why It Happens

Google released WebP in 2010 as a smaller replacement for JPG on the web, and for a decade it stayed a niche format because Safari did not display it. That changed when Apple added WebP to Safari 14 and macOS Big Sur in 2020. Once every major browser could show it, the companies that serve images at scale switched over, and they did it on the server side, where you never see the decision being made and where nothing in the page tells you which format you are actually looking at.

Shopify's image CDN, for example, hands a WebP to any browser that says it can display one, even when the product photo was uploaded as a JPG. Google Images shows its previews as WebP. WordPress has accepted WebP uploads since version 5.8 in 2021; a plan to make it convert JPG uploads to WebP by default was dropped before version 6.1 shipped, but the Modern Image Formats plugin from the WordPress performance team and many hosting image optimizers do exactly that. The result is the same everywhere: the file was a JPG on the site owner's computer and a WebP by the time it reached yours.

The browser is a willing participant. Every request Chrome, Edge and Firefox make for an image carries an Accept header listing image/webp (and image/avif), and a server that supports format negotiation reads that list and picks the smallest format you can display. When you right-click and choose Save image as, the browser saves the bytes it already received. That is why the file name can end in .jpg in the address bar and still arrive on your disk as WebP, sometimes even with a double extension like .jpg.webp.

Browsers stopped being the problem years ago. The trouble lives in everything else: desktop software installed before 2022, upload forms whose allow-list was written once and never touched, print-shop pipelines built around JPG and TIFF, and email clients that render inline images through their own decoder. None of these fail in a helpful way. A print portal just refuses the file, a government form says the format is invalid, and an older Photoshop shows a generic "could not complete your request" message that never mentions WebP.

Adobe added native WebP open and save to Photoshop in version 23.2, released in February 2022; anything older needs a third-party plugin. Lightroom Classic went years without importing WebP, so a library on an older version will silently skip those files during import. On Windows, the legacy Windows Photo Viewer cannot open WebP at all, and the Windows 10 Photos app depends on Microsoft's WebP Image Extensions package from the Store. Upload forms are the strictest group: the US Department of State's DS-160 visa photo upload, for instance, takes JPEG only, and many university application and job portals list JPG, PNG and PDF and nothing else.

WebP is unusual because one format covers both jobs: lossy compression for photographs and lossless compression with an alpha channel for graphics. When you convert out of it, you have to choose which of those two jobs the file was doing, because JPG and PNG each handle only one of them well. The question is not which format is better in general (that comparison is covered in JPG vs JPEG vs PNG) but what this particular image contains and where it is going next.

A product photo, a wallpaper, a recipe picture or a holiday snap belongs in JPG; it will be a fraction of a PNG's size and look the same. A logo, an icon, a sticker, a cut-out product on a see-through background or a screenshot full of text belongs in PNG, because JPG would either fill the transparent areas with a solid color or smear the hard edges of letters. When you cannot tell, open the file in a browser tab with a dark theme: if a checkerboard or the dark page shows through around the subject, the image has transparency and needs PNG.

Converting a lossy WebP to JPG decodes the pixels and encodes them again with a different method, so the result is not bit-for-bit identical. In practice, at JPG quality 85 to 90 the difference sits well below what you can see at normal size, even on a high-resolution screen. The visible loss in a downloaded WebP happened earlier, when the website compressed it, and converting cannot add that detail back; it only avoids adding much more on top. A second or third conversion would add up, so convert once, from the WebP you saved, rather than chaining formats.

Three things change in ways you might notice. The file grows, usually by a third or more, because JPG is the less efficient format; if a form has a KB cap, convert first and then compress it to 100 KB or whatever the limit is. Transparency is flattened: on the WebP to JPG converter the Transparent areas setting fills those pixels with White by default, or Black or a Custom color. And animation is lost, since a JPG holds one frame and only the first one is kept.

What does not change matters just as much: pixel dimensions, orientation and colors stay the same, and the embedded color profile is kept as long as Keep color profile stays on. If you are converting for print, raise Quality to 90 or above; the extra bytes cost nothing at a print lab and remove any doubt about smooth gradients in skies and skin. For uploads with a strict KB cap, 80 is usually still clean on a photo, and it leaves more room under the limit than 90 does. Below about 70, blocky edges start to appear around text and fine lines.

Before converting, it is worth checking whether the site will give you its original file, because that skips one generation of compression entirely. Whether it works depends on how the site produces its WebP. When WebP is created by a CDN on the fly, the JPG still exists on the server and the right request can fetch it. When the site stored only the WebP, as some WordPress setups do after converting uploads, there is no JPG left to get, and converting is the only route.

The tricks below are listed from most to least reliable. None of them involve anything unusual: they are ordinary browser actions and download links the site already offers. The one you will see recommended most often online, adding ?format=jpg to the end of an image address, is also the least dependable. It works only when the image CDN happens to read a parameter with that exact name, and most do not, so you get the same WebP back with no error to tell you the trick failed.

If you have saved a product catalog, a set of reference images or a folder of wallpapers, converting one file at a time gets tedious fast. The converter takes up to 20 files per batch at up to 95 MB each, applies the same Quality and Transparent areas settings to all of them and returns a single ZIP. Files are deleted from the server 30 minutes after processing, and nothing has to be installed. A folder of 100 images is five batches.

Sort the folder before you start. Put the photographs in one batch for JPG and the logos, icons and anything with a see-through background in another for WebP to PNG, so nothing ends up with a white box around it. If you work on a Mac, Preview's Export command converts single files, and command-line users can run ImageMagick's mogrify -format jpg *.webp for very large folders. Both produce the same result as a browser-based converter; the difference is only in how much setup you want.

There is no setting in Chrome, Edge or Firefox called "save images as JPG", and that is not an oversight. The browser does not choose the format; it announces which formats it can display, and the website picks one. Chrome saves exactly what it was sent, without re-encoding, which is the correct behavior: silently converting on save would add a lossy step you did not ask for. So switching browsers rarely helps either. Every current browser lists WebP in its Accept header, and they all get the same WebP from the same site.

That leaves three practical options. You can get the original through the site, using the steps above. You can install a browser extension that re-encodes the image as you save it, which is the same conversion with a different button. Or you can save the WebP and convert it when, and only when, something refuses it. The third is usually the least work, because a large share of saved images only ever get viewed on screens, where WebP opens fine in every browser, in Preview on macOS Big Sur and later, and in the Windows 11 Photos app.

If you are curious about how WebP compares with the other modern formats sites now serve, including AVIF, which is starting to replace WebP on the same CDNs, see AVIF vs HEIC vs WebP. The practical advice in this article carries over almost unchanged: an AVIF that a program refuses is solved the same way, by converting it to JPG for photos or PNG for graphics. More details on the format itself are on Google's WebP project page.