Why you end up needing to convert WebP to PNG
WebP is what most sites now serve, because it lands roughly 25 to 35 percent
smaller than a comparable JPEG and, unlike JPEG, it can carry an alpha channel.
The friction shows up the moment you save one of those images and try to use it
somewhere else. Plenty of software still refuses to open a .webp file: older
Photoshop builds, most print workflows, a lot of internal CMS uploaders, and
nearly every desktop application written before 2020. PNG is the format all of
them accept without argument.
That is the entire job of this page. It reads the WebP, hands the pixels to a canvas, and writes a PNG back out.
What survives, and what changes
Transparency survives. Both WebP and PNG store a genuine alpha channel, so a logo with a cut-out background stays cut out.
Pixel data survives too, in the sense that PNG is lossless: whatever the WebP decoded to is exactly what the PNG will contain. What it cannot do is undo damage that was already done. If the original was a lossy WebP, the compression artifacts are baked into the pixels, and PNG will faithfully preserve every one of them.
The file will get bigger, usually much bigger. A 200 KB lossy WebP commonly becomes a 1 to 2 MB PNG, because PNG spends its bytes on exactness instead of discarding detail you probably would not notice. That is the right trade when you need compatibility or a lossless source to edit from, and the wrong one when the image is going straight back onto a web page.
Lossy and lossless WebP behave differently
WebP is really two formats sharing an extension. A lossless WebP is a pixel exact container, much like PNG, and converting one produces a PNG that is identical to the source in every pixel while usually landing somewhat larger. A lossy WebP went through a codec related to VP8 video, and everything it discarded is gone before this page ever sees the file.
You can usually tell which you have from the size. Screenshots and exported graphics under a few hundred kilobytes at large dimensions are almost always lossy. Anything suspiciously large for its dimensions is probably lossless, and will convert with no visible change at all.
Batch and size limits
Files are processed one after another on your own machine, so a folder of a few hundred images is fine on a laptop and noticeably slower on a phone. Dimensions are the real ceiling: past roughly 4096 by 4096 pixels you run into the canvas area limit browsers enforce, and this tool reports that instead of handing you a blank image, which is what a naive converter does.