The short answer
There is no single best format. The right choice depends on what is in the picture. Photos have smooth gradients and noise, so lossy formats (JPG, WebP, AVIF) shrink them a lot with no visible change. Screenshots and logos have sharp edges, flat colors and text, where lossy compression leaves smudges and lossless formats (PNG, lossless WebP) stay clean.
Based on our measurements, this is what we recommend for most people:
- Photos for a website or email: WebP at quality 80 to 90, or JPG at quality 80 to 90 if the file must open everywhere, including old software.
- Screenshots with text: PNG when every letter must stay crisp, WebP at quality 90 when size matters more.
- Logos and icons: PNG or WebP. Both keep transparency, JPG does not.
- AVIF: worth trying for large photo galleries if your publishing tool can create it, but keep a JPG or WebP fallback for older devices.
Try it here: PNG to WebP
Open the full tool pagePhotos at website size: WebP vs JPG vs PNG
This is the most common case: a phone photo scaled to 1600 pixels wide for a web page or a shop listing. The table shows the file size, the quality score (PSNR, higher means closer to the original) and how long the browser took to create the file.
WebP at quality 80 came out at 96.3 KB against 179.6 KB for JPG at quality 80, with practically the same quality score (39.5 dB vs 39.2 dB). That is 46.4% smaller (calculated from the table). At quality 90 the gap was 41.2%, and at quality 70 it was 46.0%. PNG kept every pixel but needed 2777.7 KB, about 9.5 times the JPG at quality 90 and about 15.5 times the JPG at quality 80 (calculated). Reducing the PNG to 256 colors cut it to 806.1 KB, still far larger than any JPG or WebP, and with a visibly lower score of 34.4 dB.
| Format and setting | Size (KB) | PSNR (dB) | Encode time (ms) |
|---|---|---|---|
| JPG quality 90 | 291.9 | 41.7 | 18 |
| JPG quality 80 | 179.6 | 39.2 | 17 |
| JPG quality 70 | 137 | 37.9 | 13 |
| WebP quality 90 | 171.5 | 42.1 | 147 |
| WebP quality 80 | 96.3 | 39.5 | 111 |
| WebP quality 70 | 74 | 38.1 | 101 |
| PNG lossless | 2777.7 | lossless | 46 |
| PNG 256 colors | 806.1 | 34.4 | 219 |
Full-size phone photos (4000 x 3000)
The same iPhone photo at its original 12 megapixels shows the same pattern, with an even larger gap. WebP at quality 80 was 424.1 KB against 1064.9 KB for JPG at quality 80, 60.2% smaller (calculated), while the quality score was 40.3 dB vs 42.1 dB. At quality 90, WebP was 38.2% smaller than JPG with nearly the same score.
One result is worth knowing if you use an iPhone: the original HEIC file from the iPhone was 1.4 MB, and converting it to JPG at quality 90 produced 1.7 MB, 22% larger. HEIC is a modern format, and JPG needs more bytes to hold the same detail. If you convert iPhone photos only to make them open on Windows or a website, a JPG quality of 80 brings the size below the original. A lossless PNG of the photo was 14042.2 KB, roughly ten times the HEIC (calculated).
| Format and setting | Size (KB) | PSNR (dB) | Encode time (ms) |
|---|---|---|---|
| JPG quality 90 | 1720.8 | 44.3 | 145 |
| JPG quality 80 | 1064.9 | 42.1 | 112 |
| JPG quality 70 | 766.9 | 40.7 | 78 |
| WebP quality 90 | 1063.6 | 42.9 | 930 |
| WebP quality 80 | 424.1 | 40.3 | 783 |
| WebP quality 70 | 277.4 | 39.2 | 711 |
| PNG lossless | 14042.2 | lossless | 219 |
| PNG 256 colors | 4921 | 33.7 | 917 |
Screenshots and logos: where PNG and WebP win
Screenshots behave very differently from photos. Our 1280 x 800 screenshot of a web app, full of text and buttons, was 93.6 KB as a lossless PNG and 97.3 KB as a JPG at quality 90. The JPG was bigger and also damaged: its score was only 33.1 dB, which shows up as gray halos around letters and blotchy flat areas. Lossy WebP was much smaller (53 KB at quality 90, 40.2 KB at quality 80) but its score was similar to JPG, so check small text before you use it. The 256 color PNG reached 37.8 dB at 63.2 KB, the best lossy score in this group.
For the logo, a 512 x 512 app icon with flat colors, WebP at quality 90 was 7.3 KB with a score of 47.5 dB, against 20.5 KB for the lossless PNG. That is 64.4% smaller (calculated) with differences you cannot see. The 256 color PNG was actually larger than the lossless one (35.3 KB vs 20.5 KB): the icon already used few colors, so the palette step only added noise that compresses worse. Palette reduction helps PNG files with many colors, not simple graphics.
| Format and setting | Screenshot KB | Screenshot PSNR (dB) | Logo KB | Logo PSNR (dB) |
|---|---|---|---|---|
| JPG quality 90 | 97.3 | 33.1 | 13.4 | 43.4 |
| JPG quality 80 | 73.2 | 32.4 | 10.4 | 40.9 |
| JPG quality 70 | 61.7 | 31.9 | 9 | 39.7 |
| WebP quality 90 | 53 | 33.3 | 7.3 | 47.5 |
| WebP quality 80 | 40.2 | 33.1 | 6 | 45.8 |
| WebP quality 70 | 33.7 | 32.8 | 5.4 | 44.6 |
| PNG lossless | 93.6 | lossless | 20.5 | lossless |
| PNG 256 colors | 63.2 | 37.8 | 35.3 | 38.5 |
Where AVIF fits (and why it is not in our tables)
AVIF is the newest of the four. It is based on the AV1 video codec and, at similar visual quality, it usually produces smaller files than WebP, especially for photos at low and medium quality. It also supports transparency, wide color and HDR. The cost is speed: AVIF is much slower to encode than JPG or WebP, which matters when you convert thousands of images.
We did not measure AVIF because browsers do not offer an AVIF encoder to web pages. A page can ask the browser to save a canvas as JPG, PNG or WebP, but not as AVIF, so the converter on this page cannot create AVIF files and we will not publish numbers we did not measure. The converter can open AVIF files and turn them into JPG, PNG or WebP, which is useful when a site or app refuses AVIF uploads.
Current versions of Chrome, Edge, Firefox and Safari can display AVIF. Older iPhones and older desktop software may not, so sites that use AVIF normally offer WebP or JPG as a fallback.
Transparency, animation and browser support
File size is not the only thing that decides the format. Check these properties before you convert:
- Converting a transparent PNG to JPG fills the see-through areas with a solid color. In the converter above you pick that color under Background.
- Safari displays WebP but cannot save it from a web page. To create WebP files, use Chrome, Edge or Firefox.
- Upload forms of banks, government sites and some marketplaces still accept only JPG and PNG. If in doubt, send JPG.
| Feature | JPG | PNG | WebP | AVIF |
|---|---|---|---|---|
| Compression | Lossy | Lossless | Lossy or lossless | Lossy or lossless |
| Transparency | No | Yes | Yes | Yes |
| Animation | No | Rarely used (APNG) | Yes | Yes |
| Shows in current browsers | Yes | Yes | Yes | Yes |
| Opens in old software and email apps | Everywhere | Everywhere | Mostly | Often not |
| Best for | Photos everywhere | Screenshots, graphics | Photos and graphics on the web | Large photo sets on the web |
Which format for which job
These recommendations follow directly from the measurements above. Results vary with content: a photo with lots of fine detail (grass, gravel, fabric) compresses less than a portrait with a blurred background, and a screenshot of a spreadsheet behaves differently from one of a photo gallery. Use the tables as a starting point and check your own files.
| Job | Format and setting | Why, from our data |
|---|---|---|
| Photos on a website | WebP quality 80 | 96.3 KB vs 179.6 KB for JPG at the same score |
| Photos for email or any software | JPG quality 80 to 90 | Opens everywhere, 39 to 42 dB at website size |
| Archiving iPhone photos | Keep the HEIC original | JPG quality 90 was 22% larger than HEIC |
| Screenshots with small text | PNG | Lossless at 93.6 KB, smaller than JPG quality 90 |
| Screenshots where size matters | WebP quality 90 | 53 KB, check the text before sending |
| Logos and icons | WebP quality 90 or PNG | 7.3 KB at 47.5 dB, PNG 20.5 KB lossless |
| Anything that needs transparency | PNG or WebP | JPG cannot store transparency |
How we measured
We ran the test on 26 October 2026 with Anyfeat's own browser tools, the same converter and compressor you can use on this site, in Microsoft Edge 156 on Windows. Files were encoded in a background Worker, the way the tools always work, and the encode time is what the browser needed for each file.
Test images: a real iPhone photo at 4000 x 3000 (the HEIC original was 1.4 MB), the same photo scaled to 1600 x 1200, a 1280 x 800 screenshot of a web app with text and interface elements, and a 512 x 512 app icon with flat colors. Sizes are in KB, where 1 KB is 1024 bytes. The 256 color PNG is the palette reduction that the Anyfeat image compressor uses for PNG files.
Quality is PSNR in decibels, calculated by decoding each file and comparing its pixels to the original. Higher is closer to the original. In photos, differences above about 40 dB are very hard to see. PSNR is a rough guide, not a substitute for looking at the image, and it tends to undervalue how bad JPG artifacts look around text. You can repeat the test yourself: drop your own image into the converter above and press Find the smallest format to see how WebP, JPG and PNG compare on your file.