WebP vs JPG vs PNG: Which Image Format Should You Use?

Image format choice is one of the highest-leverage web performance decisions. Switching a hero image from PNG to WebP can reduce its file size by 25–35%. Switching a JPEG photo to AVIF can cut it by 50%. For a website with dozens of images, these savings compound across every page load for every visitor.

JPEG — the photo standard

JPEG (or JPG) is a lossy format designed for photographs. Its compression algorithm is tuned for continuous-tone images with gradients, skin tones, and complex textures — the kind of content in real-world photos. It handles these well at surprisingly low file sizes. It is terrible for screenshots, flat-colour graphics, and text, where its block artefacts are visible and its file sizes are larger than PNG.

PNG — the graphics standard

PNG is a lossless format designed for graphics: screenshots, diagrams, icons, logos, and anything with flat colours, sharp edges, or transparency. It compresses these perfectly. It is a poor choice for photographs — a PNG version of a typical photo will be 3–5× the size of the equivalent JPEG with no visible quality improvement.

WebP — the modern all-rounder

WebP, developed by Google, supports both lossy compression (better than JPEG by ~25–35%) and lossless compression (better than PNG by ~26%). It also supports transparency, like PNG, and animations, like GIF. Browser support is now universal (all major browsers since 2020). For web use, WebP is almost always a better choice than JPEG or PNG — smaller files with equivalent or better visual quality.

AVIF — the next-generation format

AVIF (AV1 Image File Format) achieves 40–55% better compression than JPEG and 20–30% better than WebP at the same visual quality. It supports HDR, wide colour gamut, and alpha transparency. Browser support is good (Chrome, Firefox, Safari 16+) but not universal enough for guaranteed compatibility on all older devices. Use it when you can — with a JPEG or WebP fallback.

The practical decision rule

For web: use WebP for everything, with JPEG fallback for older email clients and browsers. For images you're sharing via messaging or email where compatibility matters most: JPEG for photos, PNG for screenshots and graphics. For professional or archival use: PNG (lossless) always.