What is WebP? Google's image format, lossy and lossless, and the WebP-to-JPG question

The one-sentence answer

WebP is Google's royalty-free image format, introduced in 2010, that compresses photos ~25–35% smaller than JPG at matched quality — and can also do lossless compression with alpha transparency like a smarter PNG, using a different codec under the same.webp extension.

The two-codecs-one-extension trap

This is the thing that trips up every casual user and a fair number of professional ones. A .webp file is either:

• Lossy WebP, using the VP8 video codec to encode a single frame — analogous to JPG, targeted at photographs. Typical savings: 25–35% smaller than JPG at matched perceptual quality.
• Lossless WebP, using the VP8L codec (a purpose-built still-image codec) — analogous to PNG, targeted at graphics, UI assets, and anything with flat colour regions. Typical savings: 20–30% smaller than PNG.

Same extension, completely different codec, completely different trade-offs. A "compress my WebP" tool that doesn't know which one it's looking at will either re-encode a lossless image to lossy (destroying sharp edges) or waste time trying to recompress an already-minimal lossy frame.

Both modes support alpha transparency. That's the feature that makes WebP genuinely useful as a PNG replacement — a transparent WebP is ~25% the size of the equivalent PNG, which is why modern web design has largely moved off PNG for photo-style UI imagery.

Why Google built it in 2010

In 2010 the web ran on JPG, PNG, and GIF. JPG was 18 years old, couldn't do transparency or animation, and compressed badly on hard edges (screenshots, text, logos). PNG was lossless but huge. GIF was 256 colours, ancient, and the only option for animation. Every page a user loaded was paying the JPG/PNG/GIF tax.

Google had just bought On2 (the company behind VP8 — later VP9 and AV1) and saw an opening: take a modern video codec, rip out the inter-frame prediction, keep the intra-frame compression, slap a container around it, and you have a single-frame still image format that's smaller and more capable than JPG for nearly free. WebP shipped in 2010, with animation support added in 2012 and lossless in 2011. It's been slowly winning ever since.

The critical design choice was royalty-free. Unlike HEIC (patent-encumbered HEVC), anybody can encode or decode WebP without paying MPEG-LA a cent. That's why Chrome, Firefox, Edge, Safari, Android, and every CDN on earth now ship WebP support by default — and why paid tooling like Photoshop fought the format for a decade before caving in 2023.

WebP vs JPG vs PNG vs AVIF — the size chart

Same 12-megapixel daylight photograph, four formats, matched perceptual quality at SSIM ≈ 0.96. WebP is the comfortable middle — smaller than JPG, bigger than AVIF, universally supported today.

For lossless content (icons, UI screenshots, flat illustrations) WebP-lossless vs PNG is a different comparison entirely: a 480 KB PNG logo typically drops to 340 KB as lossless WebP — a modest but real 25–30% saving with no quality change. Larger savings for photographic sources where lossy WebP (VP8) kicks in.

Compatibility in 2026 — the good news

WebP's biggest early problem was "my browser can't open it." That's basically solved now. Real support matrix:

Practical summary: on the web, in modern apps, and on modern OSes, WebP is first-class. In email, print pipelines, and corporate Word workflows it's still occasionally awkward — hence the need for conversion tools.

What WebP does better than JPG

• 25–35% smaller at matched visual quality (real number, measured on natural photographs).
• Alpha transparency — JPG has none; WebP has full 8-bit alpha in both lossy and lossless modes.
• Sharper on text and edges — the deblocking filter handles hard boundaries better than JPG's DCT ringing.
• Lossless mode with one extension — you can round-trip a graphic through WebP-lossless and keep exact pixels; JPG's "Quality 100" is not actually lossless.
• Animation — WebP replaces GIF; a 3-second animated WebP is typically 10-30% the size of the equivalent GIF and carries 24-bit colour instead of GIF's 256.

What WebP does worse than JPG

• Encode time. cwebp is slower than mozjpeg at matched quality; not a huge gap, but noticeable on large batches.
• Colour-profile handling. ICC profile support is patchy — some encoders strip it silently, some preserve it, and wide-gamut handling is inconsistent. A Display P3 image round-tripped through the wrong WebP encoder loses saturation on export.
• Metadata. EXIF and XMP support exists but isn't as universal as JPG's. Some WebP exporters drop metadata by default.
• Progressive rendering. JPG has a mature progressive mode (the blurry-to-sharp effect as the image loads). WebP doesn't have a direct equivalent; big WebPs pop in all at once.

WebP vs PNG — when lossless WebP actually wins

Nobody markets WebP-lossless but it's quietly excellent. Typical savings on UI assets, logos, and flat illustrations:

• Web icons / logos (SVG-style flat colour): WebP-lossless ~60–80% of PNG size, zero quality change.
• Screenshots (text + UI chrome): WebP-lossless ~70–85% of PNG size.
• Photographic content you happen to keep lossless: WebP-lossless is ~95% of PNG size — marginal. For photos, use lossy WebP at Q85 and save 90%+ instead.

The catch: lossless WebP encodes slowly compared to lossy mode. A 2048×2048 screenshot can take 1–2 seconds on a modern laptop at the slowest quality setting. For server-side pipelines that's fine; for interactive tools we trade a little quality for interactivity.

Animated WebP — the GIF replacement you should already be using

A 3-second looping clip, 480×480, 30 fps:

• GIF: ~4.5 MB, 256 colours per frame, visible dithering on gradients.
• Animated WebP: ~580 KB, 24-bit colour per frame, smooth gradients.
• MP4: ~180 KB, 24-bit, smoother — but doesn't autoplay inline in every email client or chat.

Animated WebP is the middle ground: ~1/8 the size of GIF, full colour, autoplays everywhere GIF does, supported by every modern browser, embeds anywhere GIFs go. In 2026 the only reason to still export GIF is when the target is literally a system (legacy chat clients, vintage Slack integrations) that hasn't learned WebP yet.

When to convert WebP to JPG or PNG

Even in 2026 with broad WebP support, specific environments still want JPG or PNG:

• Email attachments to older Outlook / enterprise clients. JPG always. See the full WebP-to-JPG playbook.
• Print-shop submissions. Most print drivers still want JPG or TIFF. WebP is not on the allow-list.
• Legacy CMS uploaders that check extension before content type and reject unknown extensions.
• Microsoft Office documents destined for old versions of Word/Excel — Office 2019 and earlier cough on WebP-embedded content.
• Photoshop on a very old Creative Suite (pre-2022) without a plugin install.
• Giving to a collaborator whose software workflow you don't know. JPG is the Esperanto.

Converting is fast and, if the WebP was lossy, there's effectively no quality change at JPG Q90 — you're not round-tripping through a more-destructive codec, you're swapping containers for two already-lossy photo formats. If the WebP was lossless (common for screenshots), convert to PNG instead of JPG to preserve pixels exactly.

When to convert JPG or PNG to WebP

• You run a website and care about Lighthouse scores. Every image a user downloads is 25–35% lighter. On a media-heavy page that's seconds off Largest Contentful Paint. Our JPG-to-WebP tool batches this in one drag-and-drop.
• You send images through Discord, Slack, or modern chat — they all render WebP inline and the smaller file lands faster.
• You're archiving a photo library and can accept the encode time for 25–35% less disk usage.
• You're replacing PNG with transparency on a web page — a 1 MB PNG becomes 260 KB as WebP-lossless, same alpha.

How we handle WebP

We decode and encode WebP entirely in the browser via Google'slibwebp (compiled to WebAssembly). That means no upload, no server processing, and the alpha channel survives. When you convert a lossless WebP screenshot to JPG, we flag the alpha loss up-front. When you convert a lossy WebP photo to JPG at Q90, the result is visually indistinguishable. See the detailed WebP-to-JPG guide for the quality-slider and transparency decisions that actually matter.

Going the other direction — JPG to WebP for the web — we default to lossy WebP at Q80, which matches the JPG quality most competitive web-optimisers hit and usually lands around 55–65% of the source file size. Our compressor uses the same underlying encoder for direct JPG compression if you need to stay in JPG for compatibility.

Frequently asked questions

What does WebP stand for?

Officially "Web Picture". Google hasn't leaned hard on the expansion; in practice everyone says it as "webb-pee" or spells it out. It's a Google-coined trademark, not an acronym with serious weight.

Is WebP better than JPG?

For web delivery, yes — smaller files, supports transparency, supports lossless, supports animation, free and open. For compatibility outside the web (email, print, Office, legacy software) JPG still wins. "Better" depends on where the file is going.

Is WebP lossless?

It can be — lossless WebP (VP8L codec) is a separate mode from lossy WebP (VP8). Same .webp extension, different codec under the hood. If you're saving graphics with hard edges, pick the lossless mode; for photographs, pick lossy.

Does WebP support transparency?

Yes, in both lossy and lossless modes. This is one of the format's biggest wins over JPG (which has none) and a quiet win over PNG (same alpha, smaller files).

Why does Chrome serve WebP even when I right-click-saved a JPG?

Content negotiation. Many CDNs store images as WebP (or AVIF) and serve them to browsers that advertise support via the Accept header. Chrome is at the top of that list. Safari and Firefox see different content for the same URL. That's why you sometimes end up with a .webp from a page that visually shows a photo.

Can I convert back and forth without losing quality?

Lossless WebP ↔ PNG: yes, bit-exact both directions. Lossy WebP → JPG at high quality: visually indistinguishable, but technically re-encoded (two lossy passes never match one). Avoid round-tripping through many lossy conversions; pick a target and stay there.

What's the maximum WebP dimension?

16,383 × 16,383 pixels. That's a hard spec limit. For larger images (giant panoramas, print masters) you'll hit it and need PNG or TIFF instead.

Ready?

Pick the direction you need: WebP to JPG for compatibility, WebP to PNG for lossless graphics, JPG to WebP for web optimisation. Free, runs in your browser, transparent-layer safe. For the full format picture, see what HEIC is (Apple's answer) and what AVIF is (the newer, smaller alternative that's poised to take over).