If you've ever right-clicked "Save Image As" and stared at a format dropdown, you've run into this problem: JPG, PNG, WebP, and now AVIF all claim to be the "right" choice, and the honest answer is it depends on what's in the image and where it's going. Here's the practical version, without the marketing spin.

JPG: the default for photos

JPG (or JPEG) uses lossy compression — it throws away image detail your eye is unlikely to notice, in exchange for a much smaller file. That trade-off is exactly right for photographs, where there's already a ton of natural detail and noise to spare.

Best for: photos, anything with gradients, complex color, or texture.
Weak spot: sharp edges and flat colors (text, logos, UI screenshots) tend to get blurry "artifacts" around the edges.
No transparency support.

PNG: the default for graphics

PNG is lossless — it never throws away detail, which means a PNG always looks pixel-perfect compared to its source. The cost is file size: PNG has to work much harder to shrink an image without losing anything, so on a real photo it usually ends up larger than an equivalent JPG.

Best for: logos, icons, screenshots, illustrations, anything with flat color or text, and anything that needs a transparent background.
Weak spot: photos. Quality has limited effect on plain PNG output, since there's no "quality slider" that actually removes detail — you're mostly just re-encoding the same pixels more efficiently.

WebP: the modern middle ground

WebP is newer and supports both modes — lossy (like JPG, but typically 25–35% smaller at the same visual quality) and lossless (like PNG, with meaningfully better compression on most images). It also supports transparency. For most day-to-day use, WebP is simply a smaller version of whichever format you'd otherwise pick.

Best for: almost everything, if the platform you're uploading to supports it.
Weak spot: a handful of older tools, some print workflows, and a few platforms still don't accept it — which is the most common reason people end up needing to convert a WebP file back into JPG or PNG.

AVIF: the newest option, with a catch

AVIF is even newer than WebP and, in terms of pure compression, usually beats it — often 20–30% smaller than an equivalent WebP at the same visual quality, with both lossy and lossless modes just like WebP.

The catch is creating one. Every modern browser can already display AVIF files without any problem, but encoding an image into AVIF currently works reliably in Chrome and Edge — Firefox and Safari aren't there yet. That's a meaningfully different situation from WebP, which is safe to both create and use everywhere today.

Best for: squeezing out the smallest possible file when you know it'll be viewed somewhere that supports it, or you're just keeping a smaller copy for yourself.
Weak spot: encoding support isn't universal yet — treat it as an extra option to try, not your default, until browser support catches up.

So which one do you actually need?

A simple way to decide:

It's a photo, and you want the smallest reasonable file → WebP (lossy) for something safe everywhere, or AVIF if you want to squeeze out a bit more and don't need universal compatibility.
It's a logo, icon, or screenshot with text → PNG, or WebP (lossless) if the platform supports it.
You need it to work absolutely everywhere, no exceptions → JPG for photos, PNG for graphics.
You have a WebP file and the place you're uploading to rejects it → convert it to JPG or PNG.

That last case — converting out of WebP — comes up more than people expect, since a lot of exported or downloaded images are WebP by default these days, but not every tool on the other end has caught up.

Doing this without uploading your files anywhere

You can compress and convert between JPG, PNG, WebP, and AVIF — including WebP → JPG and WebP → PNG — directly in your browser with img-compress. Nothing gets uploaded to a server; the conversion happens locally on your device, so it works just as well for a private photo as it does for a public screenshot.

WebP vs JPG vs PNG vs AVIF: Which Format Should You Actually Use?