PNG vs JPG vs WebP: Which Image Format Should You Use?
How PNG, JPEG and WebP differ, when each is the right choice, and how to pick a format and quality that keep images sharp and small.
The short answer
Use JPEG for photographs when you need maximum compatibility. Use PNG for logos, screenshots, diagrams and anything with sharp edges or transparency. Use WebP for web pages when you want smaller files than either, since all current major browsers support it. The rest of this guide explains why, so you can handle the cases in between.
How compression works
Image formats store pixels in one of two ways. Lossless compression, used by PNG, finds patterns and stores them compactly, so decoding gives back exactly the original pixels. Lossy compression, used by JPEG and (optionally) WebP, deliberately throws away detail the human eye is least likely to notice, such as tiny colour variations, and so reaches much smaller sizes.
The difference shows in the content. A photograph has smooth gradients and noise, so lossy compression barely harms it and saves a lot. A screenshot of text has crisp edges against flat colour; lossy compression leaves faint blurry halos around letters, while lossless compression keeps it perfect and is already small because flat areas compress well.
JPEG
JPEG has been the photo standard since the early 1990s and opens everywhere: phones, printers, old software and email clients. You choose a quality level; around 70 to 85 percent usually looks the same as the original to most viewers at a fraction of the size. Drop much lower and blocky artefacts appear in skies and skin. JPEG has no transparency, so a transparent PNG converted to JPEG gets a solid background. Re-saving a JPEG repeatedly also compounds the loss, so keep your original and always export from it.
PNG
PNG is lossless and supports transparency, including smooth semi-transparent edges. That makes it the right format for logos, icons, UI mock-ups, charts and screenshots. Its weakness is photographs: a PNG photo can be five or ten times larger than a JPEG that looks the same. In a browser, PNG is saved without quality loss, so a compression slider does little for it. If a PNG is too big, resize it or switch format.
WebP
WebP, developed by Google, can do both lossy and lossless compression plus transparency. Typically a lossy WebP is around a quarter to a third smaller than a JPEG of comparable quality, and a lossless WebP is noticeably smaller than the equivalent PNG. It is supported by Chrome, Edge, Firefox and Safari. The remaining caveat is software outside the browser: some older editors, print shops and email clients still do not open WebP, so convert to JPEG or PNG when sending files to people rather than publishing to the web.
Size matters more than format
Before choosing a format, check the dimensions. A photo straight from a phone is often 4000 pixels wide, but a blog column displays it at under 1000. Shrinking dimensions with the Image Resizer cuts file size far more than any quality setting, because the number of pixels falls with the square of the width. Halving width and height leaves a quarter of the pixels.
A reasonable workflow for a website photo: resize so the width is about twice the displayed width (for sharp high-density screens), export as WebP or JPEG at 75 to 80 percent with the Image Compressor, and compare the result with the original at full size. If you cannot see a difference, you are done.
Quick decision table
Photo for a web page: WebP, or JPEG as a fallback. Photo to email or print: JPEG. Logo or icon with transparency: PNG (or lossless WebP). Screenshot with text: PNG. Image you will edit again: keep the original lossless file, and export copies. Use the Image Converter whenever a site or program asks for a format you do not have.
Colour, transparency and hidden data
Most web images are meant to be in the sRGB colour space, which browsers and phones display consistently. Images in other spaces can look dull or oversaturated on some screens. Re-saving an image through a browser canvas, as the Image Converter does, produces a standard sRGB result in the new format.
Photos from phones often contain metadata called EXIF, which can include the camera model, the date and even the GPS location where the photo was taken. If you post a photo online without removing it, anyone who downloads the file may read it, although many social networks strip it for you. Converting or compressing an image in the browser normally drops this data because only the pixels are re-encoded. Check the result if privacy matters.
Choosing a format for specific jobs
Social media: upload a high-quality JPEG or PNG; the platform will re-compress it anyway, so do not compress twice heavily.
Print: use a JPEG at the highest quality or a lossless format, at about 300 pixels per inch of the printed size. A 4 × 6 inch photo needs about 1200 × 1800 pixels.
Email: JPEG, resized to 1600 pixels on the longest side, is usually small and clear enough.
Logos and icons on a website: PNG for raster versions, or SVG for a vector that stays sharp at any size.
Screenshots for guides: PNG or lossless WebP, so text stays crisp.
Myths worth dropping
'PNG is always higher quality.' It is lossless, but a photo saved as a high-quality JPEG looks the same to the eye at a fraction of the size. 'WebP is not safe to use.' All current major browsers display it. 'More compression is always better.' Past a point, you save little and lose clarity. 'Quality 100 means perfect.' A JPEG at 100 is still lossy and often larger than an equivalent 90 for no visible gain.