Convexy

How to convert WebP to PNG on iPhone

This is the conversion to pick when the WebP has transparency you need to keep, or when you are handing the image to a tool that will not accept anything but PNG. It is lossless from this point forward — and considerably larger.

The formats

WebP (Google, 2010) has two distinct modes. Lossy WebP is VP8 intra-frame coding — a genuine photographic codec, roughly 25–35% more efficient than JPG. Lossless WebP is a different algorithm entirely, competitive with PNG and usually smaller. Both modes support an 8-bit alpha channel, which is a large part of why WebP took over the web: it does JPG's job and PNG's job in one format.

PNG (1996) is lossless, alpha-capable, and understood by every piece of image software ever written. That universality is the entire reason to convert.

What survives, and what doesn't

Expect the file to grow, possibly a lot. If the WebP is a photograph, the PNG can easily be 5–10x larger — lossless compression cannot compress photographic noise. If the WebP is a logo, icon or flat graphic, the PNG will be closer in size, and may even be comparable. Content decides, not the format label.

When to choose PNG over the alternatives

If you do not need transparency and just want the thing to open everywhere, JPG is smaller and equally universal. If you want to keep the file small and keep transparency, the WebP you already have is the better format — you may not need to convert at all.

No quality slider for PNG. Convexy shows a quality slider only for the lossy codecs — JPG, HEIC, WebP and AVIF. PNG is lossless and has no such dial. To shrink the output, reduce its pixel dimensions with the resize option in Options.

On-device, no upload

iOS can decode WebP natively (since iOS 14), and PNG is written with Apple's ImageIO. Convexy does the whole thing locally: no server, no account, no network call. Given how many WebP files are things people saved off the web — product shots, memes, reference images, screenshots of documents — not routing them through a stranger's converter is a reasonable default. Metadata is stripped by default; turn that off in Options if you need it kept.

How to do it

  1. Pick the WebP

    Tap Browse files and choose the .webp, or share it into Convexy from Safari, Files or another app.

  2. Choose PNG

    Convexy offers only the formats this file can genuinely become. Tap PNG.

  3. Resize if the output would be too big

    PNG is lossless, so there is no quality slider. If the source is a large photograph and the PNG would be unwieldy, set a maximum dimension in Options.

  4. Convert

    The result screen shows the input and output sizes. A large jump is expected on photographic content and is not a fault.

  5. Save or share

    Rename the file if you want, then save it to Files or Photos, or hand it to another app through the share sheet.

Common questions

Does WebP to PNG keep transparency?

Yes. Both formats support a full 8-bit alpha channel, so transparent and semi-transparent pixels are carried across exactly as they are — nothing is flattened and no background is composited in. This is the main reason to choose PNG rather than JPG, which cannot store transparency at all.

Is converting WebP to PNG lossless?

The conversion step adds no loss — PNG stores the decoded pixels exactly. But if the WebP was lossy (most on the web are), the compression artefacts already in it are preserved perfectly too. Lossless means “no further damage”, not “damage undone”. Nothing can recover what the original lossy encode discarded.

Why is the PNG so much bigger than the WebP?

Because WebP is a modern codec designed to discard imperceptible detail, and PNG discards nothing. On a photograph the difference is dramatic — often 5x to 10x. On a flat graphic or logo the gap narrows considerably, because PNG compresses large areas of uniform colour extremely well.

What about an animated WebP?

You get a single still frame. PNG is a single-image format — APNG exists but is not what a standard PNG conversion produces. If you need the animation, WebP is one of the few formats that can hold it, and converting away from it will cost you the motion.

Should I convert to PNG or just keep the WebP?

Keep the WebP if everything in your workflow can read it — it is smaller and does everything PNG does. Convert to PNG when something downstream refuses WebP, or when you need a guaranteed-compatible lossless file to edit. Converting purely out of unfamiliarity with WebP just costs you disk space.