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WebP vs PNG vs JPG: which image format?
By Himanshu Ranjan · Updated 8 November 2026
Use JPG for photos you share widely, PNG for screenshots, logos and anything needing lossless pixels or transparency, and WebP when you control a web page and want smaller files. Google reports WebP files 25 to 34 percent smaller than JPG at equal quality, though an independent 2013 study found no significant advantage.
What each format is for
JPG uses lossy compression tuned for photographs and has no transparency. PNG is lossless, supports transparency and suits screenshots, logos and text. WebP, from Google, offers both lossy and lossless modes, supports transparency in both and can hold animation. One format can do the jobs of the other two, but it is not accepted everywhere.
What the size claims actually say
Google's WebP study reported that WebP gave an additional 25 to 34 percent compression over JPG at equal or slightly better SSIM index, using an early version of the encoder (libwebp 0.1.2). Wikipedia adds that a 2013 Mozilla study did not find a significant advantage over JPG. For PNG, Google measured a 45 percent reduction for web PNGs and 28 percent against PNGs recompressed with tools such as pngcrush and PNGOUT, in 2011 measurements.
So the honest summary is that WebP can be smaller, especially against unoptimized PNG, but the gains depend on the image and the encoder. Test on your own files before assuming.
Compatibility today
Wikipedia says all major browsers now support WebP, with about 96 percent market share as of 2024. Apple briefly tested WebP in 2016 betas but removed it, and Safari added support in September 2020 with Safari 14 and macOS Big Sur. Outside browsers, support is patchier: some upload forms, older editors and email clients still reject it. A page you control can use WebP; a file you email to a stranger should usually be JPG or PNG.
- Photo for email or forms: JPG
- Screenshot or UI graphic: PNG
- Logo with transparency: PNG, or WebP on a web page
- Web page images you control: WebP, with a JPG or PNG fallback if you support old software
- Animated image: WebP or a video file, rather than GIF
Converting on a Mac
FileDial's Convert › Convert to WebP writes a new copy beside the original, keeps animated GIFs animated and does not keep metadata. That last point is a privacy bonus for photos. Convert › Convert to JPG and Convert › Convert to PNG cover the other two. To compare, convert a few real images to each format and look at the size in the result card, which shows before and after. Convert › Convert GIF to animated WebP is often smaller than the GIF.
Keep your originals. Converting a JPG to PNG does not restore detail, and PNG of a photo is large. Converting PNG to JPG drops transparency and applies lossy compression; see the PNG to JPG guide.
- Select a few images in Finder.
- Run Convert › Convert to WebP and compare sizes on the result card.
- Run Convert › Convert to JPG on a copy of the same images for comparison.
- Choose the smallest version that still looks right.
A simple rule
Default to JPG for photos and PNG for graphics. Add WebP when you publish on the web and the savings matter. Use the compression guides to shrink what you have: see compressing images on a Mac.
Mistakes and honest limits
A frequent mistake is converting the same JPG to WebP and expecting miracles. A JPG has already thrown away detail, and WebP can only encode what is left, so the gain is smaller than converting from an uncompressed source or a large PNG. Convert from the best original you have.
A second is using JPG for screenshots and logos. Lossy compression smears sharp edges and text into visible fuzz, and a PNG of a flat graphic is often small anyway. Use PNG for screenshots, charts and interface graphics, and use FileDial's Combine › Stack screenshots vertically… if you need to join several into one PNG.
A third is treating transparency lightly. JPG has none, so converting a transparent PNG to JPG fills the background, usually with white or black. WebP and PNG both keep transparency. Adjust › Remove background in FileDial writes a transparent PNG beside the original.
Fourth, mixing up animation formats. Animated WebP is generally much smaller than GIF, and Google reported a 64 percent reduction for lossy WebP converted from animated GIFs and 19 percent for lossless. Not every app displays animated WebP, so test where it will be used.
Fifth, ignoring metadata. FileDial's Convert › Convert to WebP does not keep metadata, which suits photos headed for the web, but it also drops copyright and capture dates you may want in your own archive. Keep the original for your library.
The last point is to measure. Take five representative images, convert each way and compare sizes and appearance at the zoom level your audience will use. The best format is the smallest one that still looks right for that specific purpose.
Questions
Is WebP better than JPG?
It can produce smaller files at similar quality, with Google reporting 25 to 34 percent in its study, but a 2013 Mozilla study found no significant advantage over JPG. Compatibility is the bigger difference in practice, since JPG opens in every app, form and email client.
Is WebP better than PNG?
For lossless images, Google measured a 45 percent reduction against web PNGs and 28 percent against PNGs recompressed with tools like pngcrush and PNGOUT, in 2011 measurements. WebP supports transparency, but PNG is still more widely accepted by editors and upload forms.
Does Safari support WebP?
Yes. According to Wikipedia, Safari 14 added WebP support in September 2020, along with iOS 14 and macOS Big Sur. Apple had briefly tested WebP in 2016 betas and removed it, so older Safari versions and old devices may still fail to display it.
Should I convert all my photos to WebP?
Not for your archive, where you should keep originals. Use WebP for copies you publish on web pages you control. For files you send to other people, JPG or PNG is safer, because some email clients, forms and older editors still reject WebP.