The short answer: use JPG for photos you're sending or uploading somewhere you don't control, PNG for screenshots, logos and anything that needs a transparent background, and WebP when you want smaller files and know the place showing the image supports it, such as your own website. The longer answer depends on two questions: what's in the picture, and where it's going. You can switch between the three with Image Converter, in your browser and without uploading anything.
The three formats at a glance
| JPG (JPEG) | PNG | WebP | |
|---|---|---|---|
| Compression | Lossy | Lossless | Lossy or lossless |
| Transparency | No | Yes | Yes |
| Animation | No | Only as the APNG variant | Yes |
| Best for | Photos | Screenshots, logos, text, exact copies | Both, especially on the web |
| Largest image | 65,535 × 65,535 px | 2,147,483,647 × 2,147,483,647 px | 16,383 × 16,383 px |
The dimension limits are from MDN's image format guide. They rarely matter, but an extremely wide panorama can be too big for WebP.
JPG: the default for photos
JPEG is lossy: it throws away detail your eye is unlikely to miss, which is why it can store a photo in a fraction of the space. MDN calls it a “good choice for lossy compression of still images” and the most popular. Photographs tolerate this well, because, in MDN's words, “the discarded detail is harder to see” in continuous-tone images.
Its weaknesses:
- No transparency. A transparent background has to be filled with a colour when you save as JPG.
- Sharp edges suffer. Text, thin lines and flat areas of colour pick up blur and blocky artifacts.
- Loss adds up. Each time a JPG is edited and saved again, it's compressed again.
JPG's big advantage is compatibility. MDN lists it as supported in all versions of Chrome, Edge, Firefox, Opera and Safari, and in practice almost any program, phone or upload form accepts it.
PNG: exact copies and transparency
PNG is lossless: every pixel comes back exactly as it went in. It also supports a full alpha channel, so it can store soft, partly transparent edges around a logo or a cut-out. MDN recommends PNG “for more precise reproduction of source images, or when transparency is needed.”
That makes it the right choice for screenshots, diagrams, charts, logos and anything with text. MDN's advice for these is to “prefer lossless encoding, as blurring and colored fringes around text and sharp edges are very visible.” The trade-off is size: a photo saved as PNG keeps all its detail and noise, so it ends up much larger than the same photo as a JPG.
WebP: smaller files, both ways
WebP, developed by Google, does both jobs. It has a lossy mode for photos and a lossless mode for graphics, and both support transparency and animation. Google's figures:
- Lossless WebP images are 26% smaller than PNGs.
- Lossy WebP images are 25–34% smaller than comparable JPEGs at an equivalent SSIM quality index.
- Transparency in lossless WebP costs about 22% extra bytes, and lossy WebP with transparency typically gives files about three times smaller than PNG.
MDN gives similar averages. These are typical results from the format's developers, not a promise for every image: a photo with lots of fine texture may save less, and a simple graphic may save more. MDN's general recommendation for web images is to prefer WebP or AVIF, which usually compress better than PNG, JPEG and GIF.
Where WebP can still cause trouble
In browsers, WebP is no longer a problem. MDN lists support in all versions of Chrome, Edge, Firefox, Opera and Safari, with one caveat: on a Mac, Safari needs version 14 or later and macOS Big Sur or later.
The trouble usually comes from outside the browser. If you save an image from a website and it turns out to be a .webp file, an older photo editor, office program or upload form may not accept it. When that happens, convert it to JPG, or to PNG if it has a transparent background. For websites that need to reach very old browsers, MDN suggests the <picture> element, which offers a WebP version with a JPG or PNG fallback.
Which format for which job
- A phone photo for email, a form or someone else's computer: JPG.
- Photos on your own website or blog: WebP, which loads faster for the same look.
- A screenshot with text, or a diagram: PNG, or lossless WebP on the web.
- A logo or cut-out with a transparent background: PNG or WebP. Never JPG.
- A transparent image that has to be smaller: WebP.
- An image you'll keep editing: keep a lossless master (PNG, or the original file) and export copies.
Converting between formats
Image Converter takes JPG, PNG, WebP, GIF, BMP, AVIF and SVG files, one at a time or in a batch, and saves them as JPG, PNG or WebP, plus AVIF if your browser can encode it. A quality slider appears for the lossy formats. Keep in mind what each conversion can and can't do:
- Converting can't add quality. Turning a JPG into a PNG makes a bigger file but keeps every JPG artifact. Turning a PNG screenshot into a JPG makes it smaller but can soften the text.
- Transparency becomes white in JPG, because JPG can't store it. Choose PNG or WebP to keep it.
- Animated GIFs are converted from their first frame only.
- Metadata is removed. Re-encoding drops EXIF data such as the camera model, capture date and GPS location, which is handy before posting a photo publicly.
If the goal is a smaller file rather than a different format, use Compress Image. It saves JPG or WebP with a quality slider and an optional maximum width (1920, 1600, 1280 or 600 px), and shows the new size of the first image live as you adjust. PNGs and WebPs default to WebP output so transparency is kept. It doesn't do lossless PNG optimisation, and if a result would come out bigger than the original, the original is kept instead. For photos, limiting the width usually saves more than lowering the quality.