JPG, PNG, WebP or AVIF: which image format to use

Lossy and lossless: the main difference

Lossless compression stores every pixel exactly as it was, just more compactly. Open the file again and you get back the same picture, pixel for pixel. Lossy compression throws away detail the eye is unlikely to notice, which makes files much smaller but means the original can't be recovered.

Which one suits a picture depends on its content. Photos and other images with smooth gradients tolerate lossy compression well, because the discarded detail is hard to see. Screenshots, diagrams, logos and line art don't: blurring and coloured fringes around text and sharp edges are very visible.

• JPG: lossy only.
• PNG: lossless.
• WebP: either lossy or lossless, chosen when the file is saved.
• AVIF: either lossy or lossless.

Transparency and animation

Transparency means some pixels are see-through, such as the area around a logo placed on a coloured page. JPG has no transparency at all. PNG, WebP and AVIF all support it, with smooth, partial transparency rather than only on or off.

When you convert a transparent image to JPG, the transparent parts have to become a colour. The converter fills them with the colour set in Background for transparent parts, white unless you change it. Convert to PNG, WebP or AVIF instead and the transparency is kept.

For animation, WebP and AVIF can both hold several frames, like a GIF but with far better compression. JPG and plain PNG are still pictures. The converter reads only the first frame of a GIF, so it is meant for still images, not for converting animations.

Support: what opens where

JPG, PNG and GIF work in every version of every major browser, and in practically every app and upload form. That is their great strength.

WebP now has broad support in current browsers, though older systems may lack it; on a Mac, Safari needs version 14 and macOS Big Sur or later. AVIF is newer still: Chrome and Opera added it in 2020, Firefox in 2021 and Safari in 2022. Websites that use AVIF usually provide a fallback for older browsers.

Outside the browser, support varies more. Upload forms, office software and printing services often ask for JPG or PNG, so check what the destination accepts before choosing a newer format.

A simple decision guide

Start from what the picture shows and where it's going:

• A photo for a form, an email or anyone who must be able to open it: JPG.
• A photo for your own website: WebP or AVIF for smaller files, ideally with a JPG fallback.
• A screenshot, chart or anything with small text: PNG, or lossless WebP.
• A logo or icon: SVG if you have the vector original, because it stays sharp at every size; otherwise PNG with transparency.
• Anything with a transparent background: PNG, WebP or AVIF, never JPG.
• A master copy you'll edit again later: keep a lossless version and export lossy copies from it.

Converting between formats

Changing the format can't add back quality that has already been lost. A JPG saved as PNG keeps every flaw of the JPG and usually becomes much bigger, because PNG has to store those flaws losslessly. Converting a PNG screenshot to JPG goes the other way: smaller, but with blur around text.

The image converter reads JPG, PNG, WebP, AVIF, HEIC, GIF, BMP, ICO and SVG and saves as JPG, PNG, WebP or AVIF. Pick the format under Save as, and use Quality for the lossy formats. Photo details are only written into JPG files; PNG, WebP and AVIF results are always saved without them. Everything runs in your browser, so the images are never uploaded.