Ask which image format is “best” and you'll get strong opinions. The honest answer is that each of the three common formats is built for a different kind of picture, and choosing the wrong one costs you either file size or sharpness. Sometimes both.
Rather than repeat the usual generalisations, we ran all three formats on two very different images and measured the results: a detailed 2560 × 1600 photograph, and a screenshot of a text document. The numbers below come from the same JPEG and WebP encoders that Chrome and Edge use.
The three formats in one paragraph each
JPG (or JPEG) is built for photographs. It discards detail the eye is least sensitive to, which makes photos small, but it smears hard edges such as text and lines. It has no transparency. Every device and program on earth opens it.
PNG is lossless: every pixel is stored exactly. That makes it ideal for screenshots, logos, diagrams and anything with text, and it supports transparent backgrounds. The price is that photos saved as PNG are enormous.
WebP is the newer format, from Google, and can work either way: lossy like JPG or lossless like PNG, with transparency in both modes. It's usually smaller than either. Every modern browser supports it, but some older software and some upload forms still don't. We cover that in our WebP guide.
What we measured
A photograph
| Saved as | File size | Compared with JPG 80 |
|---|---|---|
| JPG, quality 85 | 855 KB | +21% |
| JPG, quality 80 | 708 KB | — |
| WebP, quality 80 | 578 KB | −18% |
| PNG | 7.16 MB | about 10× larger |
| WebP, lossless | 5.95 MB | about 8× larger |
Two lessons. First, a photo saved as PNG is ten times larger than a good JPG, with no difference you could see. Second, WebP at the same quality setting was 18% smaller than JPG and, when we compared both against the original pixel by pixel, slightly more faithful too.
A screenshot of text
| Saved as | File size | Text edges |
|---|---|---|
| PNG | 72 KB | Perfect |
| JPG, quality 80 | 88 KB | Faint smudges around letters when zoomed in |
| JPG, quality 92 | 111 KB | Almost exact |
| WebP, lossy 80 | 36 KB | Faint softening when zoomed in |
| WebP, lossless | 24 KB | Perfect |
Here the picture reverses. JPG loses on both counts: the file is bigger than PNG and the text is less crisp. Screenshots are mostly flat colour and sharp edges, which is exactly what JPG handles worst and lossless formats handle best. Lossless WebP matched PNG pixel for pixel at a third of the size.
Which one to use
| You're working with… | Use | Why |
|---|---|---|
| Photos to share, email or upload | JPG (quality 80–85) | Small, and accepted everywhere |
| Photos on your own website | WebP | Smaller than JPG at the same quality; all modern browsers support it |
| Screenshots, documents, diagrams | PNG | Sharp text, and often smaller than JPG anyway |
| Logos and icons with transparent backgrounds | PNG (or WebP on the web) | JPG can't do transparency at all |
| An official portal or form | JPG, unless told otherwise | The safest bet for strict upload filters |
| An image you'll keep editing | PNG while editing, export at the end | Repeated JPG saves degrade a little each time |
| Printing | JPG at high quality (90+), or PNG | Print shows compression flaws that screens hide |
Size matters more than format
Before switching formats to save space, check the dimensions. In our test, switching the photo from JPG to WebP saved 18%. Simply resizing it from 2560 to 1600 pixels wide, still sharper than most screens need, took the same JPG from 708 KB to 274 KB, a 61% saving. Do both and you get down to 219 KB.
If an image is going to be viewed on a phone or in an email, resizing is almost always the bigger win. Our guide to resizing images for email has concrete sizes.
Three common misunderstandings
“PNG is higher quality than JPG”
PNG doesn't discard anything, but it can't restore what's already gone. Converting a JPG to PNG preserves the JPG's flaws exactly, in a file several times larger. Our guide to converting JPG to PNG explains when that conversion is still worth doing.
“WebP means low quality”
WebP files are small because the format is more efficient, not because it looks worse. At the same setting it measured slightly closer to the original than JPG. Its real drawback is compatibility, not quality.
“Quality 100 is safest”
For JPG, quality 100 produces a file far larger than 90 with no difference you can see. In our test, quality 95 was already 1.72 MB against 708 KB at 80. For almost every purpose, 80–85 is the sweet spot for photos.
Converting between them
All of these conversions run in your browser, so your images aren't uploaded. The image compressor can also output WebP directly.
Image Compressor Make the file smaller without making the picture worse.
PNG to JPG Pick a background colour and quality level before converting.