WebP vs PNG: Which Is Better for the Web?

PNG and WebP solve overlapping problems (both handle transparency, both can be lossless) but their file-size profiles differ a lot. This guide covers which to pick when, with real numbers from common image types.

The short answer

For web delivery in 2026: WebP wins almost every time. It's smaller for the same visual quality, supports the same alpha channel, and has a lossless mode that competes with PNG.

PNG is still the right answer for: lossless screenshots you'll edit again, exports that need to round-trip into PNG-aware tools, and pixel-art at very small sizes where WebP's encoder occasionally gets in its own way.

File size: real numbers

Photograph with transparency (4000×3000, masked subject)

• PNG (lossless): 8.4 MB
• WebP (lossless): 5.1 MB
• WebP (quality 90): 540 KB

WebP lossless is consistently ~40% smaller than PNG. If you can tolerate visually-imperceptible lossy compression, you save another order of magnitude.

Flat-colour graphic (1080×1080, icon)

• PNG-8 (256 colors): 28 KB
• WebP (lossless): 22 KB
• WebP (quality 90): 19 KB

For graphics, the gap narrows but WebP still wins.

Screenshot of a webpage (1920×1080)

• PNG: 480 KB
• WebP lossless: 240 KB
• WebP quality 85: 110 KB

The screenshot case is where WebP shines: repeating UI elements compress brilliantly.

When PNG still wins

• You need to edit the file again. PNG round-trips losslessly through every editor. WebP lossless does too, but some tools downconvert on save.
• Pixel art at tiny sizes. A 32×32 sprite is a single PNG chunk; WebP's overhead can occasionally make it larger.
• Legacy document workflows. Some PDF readers, some email systems, some embedded software won't render WebP.

When WebP wins

• Anything shipped to a browser. WebP is universally supported in 2026.
• CDN bandwidth. Half the bytes for the same image equals lower bills.
• Image-heavy sites. Compound the savings across a gallery and the page weight drops dramatically.
• Apps that bundle images. App size matters; WebP shrinks your binary.

Alpha channel quality

Both formats support an alpha channel. PNG-32 gives you 8 bits per channel = 16.7 million colours plus alpha, completely lossless. WebP lossless matches that. WebP lossy alpha looks great at quality ≥ 85; at lower qualities, look closely at edges before shipping.

How to convert

OmegaPix runs everything client-side via WASM: your PNGs never leave your browser:

• PNG to WebP, single-purpose tool, fastest for batches
• Image Compressor, also handles JPEG, AVIF, HEIC input
• PDF Metadata Remover, unrelated, but useful if you've converted PNG screenshots from a PDF

Recommendation

Default to WebP for new web content. Convert your existing PNG library to WebP and serve via <picture> with PNG fallback if you support any pre-2018 browsers. For everything else, PNG is fine.