WebP vs PNG: Which Should You Use?

You are probably here for one of two reasons. Either a website handed you a .webp file and something else, an editor, an upload form, a craft tool, refused to take it. Or you are building something of your own and deciding which format to serve. Good news either way: this is not a fight with one winner. WebP and PNG are tools for different rooms, and once you know which room you are in, the choice makes itself.

What each format actually is

PNG dates from the mid-1990s and does exactly one kind of compression: lossless. Every pixel you put in comes back out. That, plus thirty years of adoption, is why it opens in every editor, uploader, office suite, and print shop on the planet. The cost is size: PNG was never designed for photographs, and a photo saved as PNG is enormous.

WebP is Google's format from 2010, built for the web. It does both lossy compression (like JPG, throwing away detail your eye will not miss) and lossless compression (like PNG, keeping every pixel), and it supports animation. In both modes it tends to produce smaller files than the older format doing the same job, which is exactly why so many websites now hand you .webp files whether you asked for one or not.

Compression: WebP's home turf

For photos, it is not close. PNG has no lossy mode, so a photograph in PNG carries every pixel at full weight, while lossy WebP shrinks it dramatically at quality levels most people cannot tell apart from the original. If a photo is going on a web page, PNG is the wrong container for it.

For graphics, logos, and screenshots, both formats can be lossless, and WebP's lossless mode usually comes out smaller than PNG for the same image. How much smaller varies from image to image, so test with your own files rather than trusting anyone's headline figure, ours included. The point is direction, not decimals: same pixels, fewer bytes.

Transparency: a tie

Both formats support full alpha transparency, meaning soft edges and partially see-through pixels, not just on-off cutouts. WebP keeps transparency in its lossy mode too, which is something JPG never managed. So transparency alone should never decide this choice. The deciding factor is the next section.

Compatibility: PNG's home turf

PNG opens everywhere. Not almost everywhere: everywhere. Any editor, any upload form, any school portal, any print service, any embroidery or vinyl program from 2009. That universality is the entire reason the format is still the default handoff for images.

WebP displays in every current browser, and most modern software reads it, but the long tail is real. Upload forms with old validation lists, older versions of desktop editors, office tools, and a fair amount of craft and maker software will reject a .webp without explanation. If you have ever renamed a file three times wondering why a form keeps spitting it out, you have met this wall. (ButterySpace's own image tools take PNG, JPG, and WebP equally, but we are not the picky uploader you will meet next week.)

When to pick which

You are doing	Pick
Uploading to a form, portal, or service that might be picky	PNG
Serving photos on your own website	WebP (lossy)
Serving logos or UI graphics on your own website	WebP (lossless)
Keeping a master copy you will edit later	PNG
Sending an image to someone whose software you do not know	PNG
Feeding a maker tool (vectorizer, lithophane, bookmark)	Either works in ButterySpace; PNG is the safer bet elsewhere

How to convert between them

Whichever direction you need, the conversion is a one-minute job:

1. Open the converter. Go to ButterySpace's Convert Format tool. It runs online from any browser on any device, no install and no sign-in.
2. Drop your image. Drag in the WebP or PNG, or click to browse. Files up to 20 MB are fine.
3. Pick the output. Choose PNG when you need a file everything opens, or WebP when the destination is the web. Transparency survives in both directions.
4. Convert and download. Hit Convert image and download the result. A conversion costs 1 pat of the five free ones you get each day, and uploads auto-delete within 24 hours.

One honest note on direction: converting a lossy WebP to PNG wraps the pixels in a format everything opens, but it cannot restore detail the lossy compression already discarded. The PNG is a faithful copy of the WebP, not of whatever original produced it. Going the other way, PNG to WebP, starts from lossless pixels, so you control what, if anything, gets traded for size. If one direction is the one you keep needing, the WebP to PNG and PNG to WebP pages are the same converter with that job preset.

Quick answers

Does WebP support transparency?

Yes. Both WebP and PNG support full alpha transparency, and WebP keeps it in both its lossy and lossless modes. The old advice that transparency means PNG is out of date. What PNG still wins on is compatibility: every app on earth opens it, which is not yet true of WebP.

Why do some sites and apps reject WebP?

Every current browser displays WebP, but plenty of upload forms, older desktop programs, office suites, print services, and craft software validate against an older list of formats and turn it away. The file is fine; the gatekeeper is picky. Converting to PNG is the universal unlock.

Is lossless WebP smaller than PNG?

Usually, yes. For the same pixels, WebP's lossless mode typically produces a smaller file than PNG, though the gap varies by image and neither loses any quality. For photos, lossy WebP is dramatically smaller than PNG, because PNG has no lossy mode at all.

Should I convert my site's PNGs to WebP?

For images that only ever appear on web pages, it is usually worth it, especially for photos and large graphics. Keep your original PNGs as masters and serve WebP copies. For files people download, upload elsewhere, or edit, stay with PNG so nobody hits a compatibility wall you created to save kilobytes.