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JPG, PNG, WebP or AVIF: Which Image Format Should You Use?

4 min read4 October 2026By Muhammad Abdullah

Images are usually the heaviest thing on a web page, and the format you save them in decides a large part of that weight. Pick the wrong one and a page loads several times more data than it needs to. Pick the right one and nobody can see the difference except in how fast the page appears.

Try it as you readResponsive Image srcset GeneratorGenerate srcset and sizes markup, with a WebP source and correct width and height so the layout never shifts.

Two kinds of compression

Every format is either lossless or lossy. Lossless compression shrinks the file but keeps every pixel exactly as it was, so you can save it again and again with no change. Lossy compression throws away detail the eye is unlikely to notice, which makes files far smaller, but each save loses a little more.

The question for any image is simply: does this need every pixel exact, or does it need to look right? A screenshot of code needs exact pixels. A photo of a beach needs to look right.

The formats, one at a time

  • JPG: lossy, made for photographs. Small files for images full of soft colour changes. No transparency, and it smears sharp edges like text and lines.
  • PNG: lossless, with transparency. Ideal for screenshots, diagrams and logos with flat colour. Very large for photos, often five to ten times a JPG of the same picture.
  • WebP: can be lossy or lossless, and supports transparency. Usually around a quarter to a third smaller than a JPG or PNG at the same visual quality. Every current browser supports it.
  • AVIF: newer, and often smaller again than WebP, especially at low file sizes. Supported by current Chrome, Edge, Firefox and Safari. Slower to encode, which matters only when you are converting many images.
  • SVG: not pixels at all but shapes described in code. Perfect for icons, logos and simple illustrations, because it stays sharp at any size and is often tiny.
  • GIF: old, limited to 256 colours, and very heavy for animation. A short muted video in MP4 or WebM is usually a fraction of the size.

A simple rule that covers most images

  • Icons and logos: SVG if you have it, otherwise PNG or lossless WebP.
  • Photos: WebP or AVIF, with JPG as the fallback if you need one.
  • Screenshots and anything with text in it: PNG or lossless WebP. Lossy formats blur small text.
  • Animation: a video file, not a GIF.

Serving the right size and format

You do not have to choose one format for every visitor. The picture element lets the browser take the best format it understands, and srcset lets it take the right width for the screen.

html
<picture>
  <source type="image/avif" srcset="hero-800.avif 800w, hero-1600.avif 1600w">
  <source type="image/webp" srcset="hero-800.webp 800w, hero-1600.webp 1600w">
  <img src="hero-800.jpg" srcset="hero-800.jpg 800w, hero-1600.jpg 1600w"
       sizes="(max-width: 800px) 100vw, 800px"
       width="1600" height="900" alt="Beach at sunset" loading="lazy">
</picture>

The browser reads the sources from the top and uses the first type it supports, so AVIF goes first, then WebP, with the plain img as the fallback. Setting width and height lets the page reserve the right space before the image arrives, so the layout does not jump.

Leave loading="lazy" off the main image at the top of the page. Lazy loading delays it, and that image is usually the one the visitor is waiting for.

Quality settings

For lossy formats, a quality setting around 75 to 85 is usually indistinguishable from the original at normal viewing size, at a fraction of the bytes of 100. Going above 90 adds a lot of weight for detail almost nobody sees. Check the result at the real display size rather than zoomed in, because that is how visitors will see it.

Common questions

Is WebP better than PNG?

For most web images, yes. Lossless WebP keeps every pixel like PNG but is usually smaller, and lossy WebP is far smaller still for photos. PNG remains a safe choice where exact pixels matter and size does not.

Should I use AVIF?

If you can generate it, yes, inside a picture element with WebP or JPG as a fallback. It is often the smallest option, and current major browsers support it.

Why does text in my JPG look blurry?

JPG is lossy and smears sharp edges. Save screenshots and images with text as PNG or lossless WebP instead.

Tools from this guide

PerformanceResponsive Image srcset GeneratorGenerate srcset and sizes markup, with a WebP source and correct width and height so the layout never shifts.HTMLImage Tag GeneratorGenerate img markup with alt text, explicit dimensions, lazy loading and fetchpriority, optionally wrapped in a figure with a caption.PerformancePage Weight and Load Budget CalculatorAdd up your page weight, see it against a performance budget, and estimate load time on slow connections.

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