Transparency survives the trip
WebP and PNG both carry an 8-bit alpha channel, so transparent and semi-transparent pixels are copied as they are — no background colour is involved. After conversion the row shows what share of the image is transparent, so you can confirm a cut-out logo really kept its transparency.
If the WebP was saved with lossy compression, its soft edges already contain small errors. PNG preserves them exactly; it cannot clean them up.
Why the PNG is so much bigger
PNG is lossless, while most WebP files on the web are lossy. In our tests the same pictures were 7.7 to 26 times larger as PNG than as WebP at quality 80: 9,786 vs 75,480 bytes for a 512×512 icon, and 29,640 vs 783,179 bytes for a 768×512 photo.
That growth is expected, and the row note shows the multiple for each file. If you only need the image to open somewhere, WebP to JPG gives a much smaller file; use PNG when you need transparency or a lossless copy to edit.
Which apps need PNG
- Older versions of image editors and office suites that cannot open WebP.
- Slide decks, documents and design tools where a transparent PNG is the safe choice.
- Upload forms, stores and print services that list PNG and JPG only.
Animated WebP becomes one still image
An animated WebP holds several frames. PNG output here is a single still image (not animated PNG), so only the first frame is saved; the row reports how many frames the file had.
If you need every frame, use a dedicated frame-extraction tool; this page is built for still images.
Large PNGs, rough edges and files that won’t open
- The PNG is too large: use Max width under Resize, or keep a WebP or JPG copy for sharing.
- Edges look rough on a dark background: the WebP’s lossy alpha is kept exactly; export a new WebP or PNG from the original design if you have it.
- The file came from a website and will not open: check it really is WebP; this page also accepts JPG, PNG, GIF and AVIF dropped by mistake and converts them to PNG too.