Choosing the wrong image format is one of the most common reasons web pages load slowly, logos look blurry, or photos take up far more space than they should. The format you pick decides three things at once: how sharp the image looks, how small the file is, and whether it can have a transparent background. This guide explains the four formats that actually matter today — JPG, PNG, WebP, and AVIF — and gives you a simple rule for each situation.
The 30-second answer
- Photographs for the web? Use WebP (or JPG if you need maximum compatibility).
- Logos, icons, screenshots, or anything with transparency? Use PNG (or WebP for smaller files).
- Squeezing the absolute smallest file size on a modern site? Use AVIF, with a WebP or JPG fallback.
- Sending to a printer or a client who needs universal support? Use JPG for photos, PNG for graphics.
If you only remember one thing: lossy formats (JPG, WebP, AVIF) are for photos; lossless formats (PNG) are for graphics with sharp edges and flat colors.
JPG (JPEG) — the universal photo format
JPG has been around since 1992 and every device on earth can open it. It uses lossy compression, which means it permanently throws away some image data to make the file smaller. For photographs — where millions of subtle color shifts hide the loss — this is barely noticeable and the space savings are huge.
Use JPG when:
- You’re saving a photograph and need it to open anywhere.
- The image has no transparent areas (JPG can’t store transparency).
- You’re emailing photos or uploading where the platform expects JPG.
Avoid JPG when:
- The image has sharp text, hard edges, or flat color areas — JPG creates ugly “halo” artifacts around them.
- You need a transparent background.
- You’ll re-edit and re-save the file many times. Every save degrades it a little more (this is called generation loss).
PNG — the format for graphics and transparency
PNG uses lossless compression: it shrinks the file without throwing any data away, so the image is pixel-perfect every time. That makes it ideal for anything with crisp edges — logos, icons, screenshots, diagrams — and it’s the only one of the classic formats that supports a fully transparent background.
Use PNG when:
- You need transparency (a logo that sits on any background colour).
- The image is a screenshot, illustration, or contains text.
- You can’t tolerate any quality loss.
Avoid PNG when:
- You’re saving a full-colour photograph — PNG files for photos are often 5–10× larger than the JPG equivalent for no visible benefit.
If you have a photo saved as a giant PNG, converting it to JPG or WebP can cut the file size dramatically.
WebP — the modern all-rounder
WebP, developed by Google, is the format most websites should default to in 2026. It supports both lossy and lossless compression and transparency, and it’s typically 25–35% smaller than JPG at the same visual quality, or much smaller than PNG for graphics. Every current browser supports it.
Use WebP when:
- You’re publishing images on a website and want fast load times.
- You need transparency but want files smaller than PNG.
- Your audience uses reasonably modern browsers (essentially everyone today).
The one catch: some older desktop software and a few email clients still don’t read WebP. If you’re handing a file to a non-technical client, JPG or PNG is the safer bet.
AVIF — the smallest files, with a catch
AVIF is the newest format here, based on the AV1 video codec. It produces the smallest files of all — often 50% smaller than JPG — while preserving detail remarkably well, and it handles transparency and high-dynamic-range colour. The trade-offs are slower encoding and slightly less universal support than WebP.
Use AVIF when:
- You run a performance-focused website and can serve a fallback (
<picture>with WebP/JPG) for the rare browser that can’t read it. - You want the best possible compression and have time to encode.
Quick comparison table
| Format | Compression | Transparency | Best for | File size (photo) |
|---|---|---|---|---|
| JPG | Lossy | ❌ No | Universal photos | Medium |
| PNG | Lossless | ✅ Yes | Logos, screenshots, transparency | Large |
| WebP | Both | ✅ Yes | Modern websites | Small |
| AVIF | Both | ✅ Yes | Maximum compression | Smallest |
A practical workflow
- Photo for a website? Export as WebP. If you must support every old browser, keep a JPG fallback.
- Logo or icon? Keep a master PNG; export a WebP copy for the web.
- File too big? Don’t just convert — also compress it to trim the last unnecessary kilobytes.
- Need a specific format a platform demands? Convert it in seconds, right in your browser — nothing is uploaded to a server.
The bottom line
There’s no single “best” format — only the best format for a specific job. Reach for WebP as your everyday default on the web, PNG whenever you need crisp edges or transparency, JPG when universal compatibility matters most, and AVIF when you’re chasing the smallest possible files. Get this one decision right and your images will look better and load faster everywhere.