WebP and AVIF produce noticeably smaller files than JPEG at the same visual quality, which is why so much of the web has quietly switched to them. Actually converting a file into one of these formats on your own machine, though, turns out to be less obvious than it should be, especially on Windows.
In this article
This guide covers why these formats are worth using, and how to actually convert into them, not just view them, on Windows and Linux.
Key takeaways
- WebP typically produces files 25 to 35 percent smaller than JPEG at equivalent visual quality; AVIF often goes further, sometimes 30 to 50 percent smaller.
- Windows' built-in WebP support only lets you open and view WebP files. It doesn't let you save or convert into the format.
- Converting into WebP or AVIF on Windows needs a third-party app or a command-line tool.
- Linux has solid command-line tools for both,
cwebpfor WebP andavifencfor AVIF.
Why convert to WebP or AVIF at all
Both formats were built specifically to beat JPEG's compression efficiency at the same visual quality, and independent testing backs that up: WebP generally runs 25 to 35 percent smaller than JPEG for the same quality, and AVIF often goes further still, sometimes 30 to 50 percent smaller, though the gap narrows on photos with a lot of fine detail.
For a website, that's a direct speed win. For anything with a strict upload size limit, it's often the easiest way to fit under it without resizing the image down further than you'd like.
Converting on Windows
Windows 10 and 11 can open and view WebP files once the free WebP Image Extension is installed from the Microsoft Store, and Paint can open one. What trips people up is that this support is a viewer, not an encoder: Paint can open a WebP file and save it as JPEG or PNG, but it can't do the reverse and save a JPEG or PNG as WebP.
To actually convert into WebP or AVIF on Windows, you need either a desktop app built for it (GIMP and Paint.NET both export WebP directly) or a command-line tool like cwebp. Image Tools does this natively as one of its export formats, without needing a second app just to get the format conversion itself.
Converting on Linux
cwebp handles WebP conversion. Install it with sudo apt install webp on Debian or Ubuntu, or the equivalent for your distribution, then run cwebp -q 85 image.jpg -o image.webp, where the number after -q sets the quality from 0 to 100.
avifenc, from the libavif project, handles AVIF: avifenc input.png output.avif for a default conversion, or avifenc -q 65 input.png output.avif to set the quality explicitly. Both tools support running in a loop to batch-convert a whole folder at once.
Common mistakes
- Assuming WebP support means export support. Windows' native WebP handling only covers opening and viewing the format, not saving into it.
- Converting at full quality by default. Both
cwebpandavifencdefault to reasonable settings, but checking the quality flag explicitly avoids surprises in file size. - Converting for a destination that doesn't support the format yet. A handful of older systems and upload forms still reject WebP or AVIF outright; check before committing to it as the only copy.
- Losing track of which files were already converted. Batch conversions in a shared folder can get confusing fast without a clear naming convention or a separate output folder.
FAQ
Can Windows open WebP files without installing anything?
Recent versions of Windows 11 handle this out of the box in some cases, but the free WebP Image Extension from the Microsoft Store is the reliable way to guarantee it works, including in Paint and File Explorer thumbnails.
Is AVIF always better than WebP?
Usually smaller at the same quality, yes, but AVIF encoding is slower and support is a little less universal than WebP's at this point. For most uses the difference matters more for very large batches than for a handful of images.
Do I lose quality converting JPEG to WebP or AVIF?
Converting between two lossy formats always involves some re-compression. Keeping the quality setting reasonably high, 80 or above, keeps the difference hard to notice in practice.
The bottom line
WebP and AVIF are worth using when file size matters, but actually converting into them, especially on Windows, usually means reaching for a dedicated tool rather than what's already installed.
Image Tools converts to WebP and AVIF directly, alongside JPEG, PNG, and the rest, on Windows and Linux, with nothing uploaded to do it. The free trial covers a limited number of images with no account needed.
