Three image formats cover almost every use case in digital work: JPEG (JPG), PNG, and WebP. Each has different strengths, and choosing the wrong one either bloats your file sizes unnecessarily or costs you quality. This guide gives you a clear framework for picking the right one every time.
JPEG — the workhorse for photographs
JPEG (Joint Photographic Experts Group) was designed specifically for photographs, and it's excellent at its job. It uses lossy compression that targets the parts of an image the human eye is least sensitive to, achieving dramatic size reductions — a 10 MB RAW photo can become a 300 KB JPEG with no perceptible difference on screen.
Use JPEG for: photographs, realistic illustrations, any image with gradual colour transitions, images being shared over email or to platforms with limited format support.
Avoid JPEG for: images with transparent backgrounds (JPEG has no alpha channel), screenshots, logos, text-heavy images (the lossy compression creates visible artefacts around sharp edges), and any image you plan to edit and re-save multiple times (each save re-applies compression and degrades the image further).
PNG — lossless and transparent
PNG (Portable Network Graphics) uses lossless compression — every pixel is stored exactly. No quality is ever lost, regardless of how many times you save the file. The trade-off is that file sizes are much larger than JPEG for photographic content.
Use PNG for: logos, icons, UI screenshots, anything with a transparent background, images with text or sharp edges, and source files you'll edit later.
Avoid PNG for: photographs and images with many colours where you don't need lossless quality. A photograph saved as PNG can be 5–10× larger than the same image as a JPEG with no visible quality advantage for screen display.
WebP — the modern all-rounder
WebP was developed by Google and released in 2010. It supports both lossy compression (like JPEG) and lossless compression (like PNG), plus a full alpha channel for transparency. At the same visual quality as JPEG, WebP is typically 25–35% smaller. At the same visual quality as lossless PNG, WebP is typically 25–35% smaller.
Use WebP for: any image served on a modern website, replacing both JPEG photographs and PNG graphics with transparency. As of 2024, over 96% of browsers globally support WebP.
The main limitation of WebP is compatibility outside the browser: some email clients, older applications, and print workflows still don't support it. For anything leaving the web ecosystem, JPEG or PNG remains the safer choice.
Decision framework
- Photo on a website → WebP (lossy, smallest file)
- Photo in an email or non-web context → JPEG
- Logo or icon with transparent background on a website → WebP (lossless) or PNG
- Screenshot or UI graphic on a website → WebP
- Source file for editing → PNG (lossless, no re-compression degradation)
- Image for print → JPEG at 90%+ or lossless PNG
What about AVIF, HEIC, and other formats?
AVIF is a newer format that achieves even smaller files than WebP at the same quality. Browser support is growing but not yet universal, and encoding is slower. HEIC is Apple's default photo format, excellent in quality but with limited non-Apple platform support. For most practical purposes in 2025, WebP is the best balance of compression efficiency and compatibility for web use.