For photographs, use JPG. For graphics that need transparency or crisp edges — logos, icons, screenshots of text — use PNG. For the smallest files on a website, use WebP, which beats both at similar quality. The best image format for websites is usually WebP with a JPG or PNG fallback, and you can convert between all three privately in your browser with nothing uploaded.
The short answer
There's no single "best" format — each is built for a different job. JPG wins for photos, PNG wins for transparency and hard edges, and WebP is the modern all-rounder that usually produces the smallest file. Pick by what the image contains and where it's going, not by habit.
JPG — best for photographs
JPG uses lossy compression tuned for photographs: it throws away detail the eye barely notices to reach small file sizes on images with smooth gradients and lots of colour, like camera photos. That's its strength and its weakness. Photos look great and stay small; but every time you save a JPG it re-compresses, so repeated edits slowly degrade it, and it can't store transparency. It's the right choice for photo-heavy pages, email attachments, and anywhere compatibility matters — JPG opens literally everywhere. Convert to it with PNG to JPG or WebP to JPG.
PNG — best for transparency and sharp edges
PNG is lossless, so pixels are preserved exactly, and it supports a transparent background. That makes it the format for logos, icons, illustrations, diagrams, and screenshots — anything with sharp lines, flat colour, or text, where JPG's compression would smear fuzzy artefacts around the edges. The trade-off is size: a PNG photo can be several times larger than the JPG equivalent. Use PNG when crispness or transparency matters, not for full-colour photographs. Convert with JPG to PNG or WebP to PNG.
WebP — best for small web files
WebP is the newer format designed for the web, and it does something neat: it offers both lossy and lossless modes, plus transparency. In practice a WebP is typically 25-35% smaller than the equivalent JPG (per Google's published WebP figures), and smaller than PNG for graphics, at visually similar quality. That directly improves page load speed, which is why it's the go-to for website images today. The catch used to be support, but every current browser now handles WebP. Convert with JPG to WebP or PNG to WebP.
How to choose, quickly
- A photograph for a website → WebP (fall back to JPG for very old software).
- A photo for email or maximum compatibility → JPG.
- A logo, icon, or anything with a transparent background → PNG, or WebP if the target supports it.
- A screenshot of text or a sharp-edged diagram → PNG (or lossless WebP) to keep edges crisp.
- You just need the file smaller for the web → convert to WebP.
The honest trade-offs
No format is free of downsides. JPG is universal but lossy and can't do transparency. PNG is pixel-perfect and supports transparency but produces large photo files. WebP is smaller and flexible but is a web-era format, so a few very old or niche programs still won't open it — which is why keeping a JPG or PNG fallback is sensible for anything you'll hand to others. Don't convert a JPG to PNG hoping to "restore" quality, either: the detail JPG discarded is already gone, and the PNG will just be a bigger file of the same image.
Convert between them privately
Whichever way you're converting, it happens in your browser on your own device — the image is never uploaded, there's no sign-up, and it works offline. That matters for personal photos, product shots you haven't launched, or client work. Pick the pairing you need — JPG to WebP, PNG to WebP, WebP to JPG, PNG to JPG, or JPG to PNG — and the file stays with you the whole time.