Guide · Updated 2026-10-08
JPG vs PNG vs WEBP: Which Image Format Should You Use?
How the three common web image formats differ, with measured file sizes from our own test images, and a simple rule for choosing between them.
Three formats cover almost every image on the web: JPG, PNG and WEBP. They are not interchangeable, and picking the wrong one costs you either file size or quality. This guide explains the differences and shows what happens to a file when you convert it with the Image Converter.
What each format is good at
| Format | Compression | Transparency | Best for |
|---|---|---|---|
| JPG | Lossy | No | Photographs, where small files matter and tiny detail loss is invisible |
| PNG | Lossless | Yes | Logos, screenshots, line art and anything with sharp edges or transparency |
| WEBP | Lossy or lossless | Yes | Almost anything on the web, when your audience uses modern browsers |
What conversion does to file size: a measured test
We made a synthetic 1600 × 1000 pixel picture (a colour gradient with noise and shapes, so it behaves like a photo) and converted it in Chromium with the Image Converter. These are real results from that one image, not a promise for yours.
| Conversion | Starting size | Result |
|---|---|---|
| JPG to PNG | 82.7 KB | 1.07 MB |
| JPG to WEBP | 82.7 KB | 59.2 KB (about 28% smaller) |
| PNG photo to JPG | 1.63 MB | 94.7 KB |
| PNG photo to WEBP | 1.63 MB | 49.5 KB |
| WEBP to PNG | 45.7 KB | 502.8 KB |
| WEBP to JPG | 45.7 KB | 80.0 KB (larger) |
Two lessons stand out. First, converting a lossy photo to PNG makes the file far larger without bringing back any detail that was already lost. Second, WEBP is not always the smaller option when you convert from it: the 45.7 KB WEBP became an 80 KB JPG.
Transparency
JPG cannot store transparency. When a transparent PNG is converted to JPG, the see-through areas are filled with white, as the converter does. A transparent 800 × 600 logo (361.8 KB as a PNG) became 72.5 KB as a JPG with a white background, and 60.9 KB as a WEBP with the transparency kept. If your logo sits on a coloured page, use PNG or WEBP.
A simple rule for choosing
- Photograph for a web page: WEBP, or JPG if you need to support very old software.
- Logo, icon or screenshot: PNG, or lossless WEBP.
- Needs transparency: PNG or WEBP, never JPG.
- Email attachment or upload form that rejects WEBP: JPG for photos, PNG for graphics.
- Archive or further editing: keep the original, and convert copies. Every lossy save loses a little more.
Convert, then shrink
Converting changes the format. It does not choose a quality for you: the converter saves JPG and WEBP at a fixed 92% quality. To go smaller, resize the picture to the size it will actually display with the Image Resizer, then lower the quality in the Image Compressor. In our compressor test, the same 5.29 MB PNG became 417 KB at WEBP quality 75 and only 33 KB when it was also capped at 800 pixels wide.
Frequently asked questions
Does converting JPG to PNG improve quality? No. PNG stores what it is given without loss, but it cannot restore detail the JPG has already thrown away.
Is WEBP supported everywhere? All current major browsers display it. Some older desktop software and email clients do not, so keep a JPG or PNG copy when sharing files outside the web.
Does the converter upload my image? No. The conversion runs in your browser.