What is a WebP file?

A practical guide · Updated June 2026

If you have ever right-clicked an image online, chosen "Save as," and ended up with a file ending in .webp that your usual photo app refused to open, you have already met WebP. It is now one of the most common image formats on the web, yet plenty of people have never heard of it until a stray download leaves them stuck. This guide explains exactly what a WebP file is, why Google created it, what it can do that JPG and PNG cannot, how to open and convert one, and when it is the right choice. No jargon — just the practical details.

What exactly is a WebP file?

WebP (pronounced "weppy") is a modern image format that stores photos and graphics in a smaller file than the older formats it was designed to replace. Files use the .webp extension and the image/webp media type. Under the hood, a WebP file is a RIFF container — the same box-like file structure used by WAV audio and AVI video — that wraps compressed image data derived from the VP8 video codec. In plain terms: Google took the clever maths that makes video frames small and applied it to still images.

Because of that heritage, WebP is unusually flexible. A single format can hold a heavily compressed photograph, a pixel-perfect logo with a transparent background, or a short looping animation — jobs that used to require three separate formats (JPG, PNG and GIF). That versatility, combined with smaller file sizes, is the whole reason it exists.

Why Google created WebP

WebP was announced by Google on 30 September 2010, and its purpose was blunt: make the web faster. Images are the heaviest part of most web pages, so shrinking them shrinks load times, saves bandwidth, and improves the experience for everyone — especially on mobile. Earlier that year Google had acquired On2 Technologies, a video-compression company, and WebP grew directly out of On2's VP8 codec.

Google's motivation was not purely altruistic. Faster pages keep people browsing (and clicking ads), and Google's own products — Search, Photos, YouTube thumbnails, the Play Store — serve billions of images a day, so even a 30% size cut is an enormous saving. Page speed later became an explicit ranking signal through Core Web Vitals, which gave every website owner a reason to care too. WebP is simply the format that lets you send the same picture using roughly a third less data.

Lossy, lossless, transparency and animation

The reason WebP can stand in for three older formats is that it supports four capabilities that were previously split across them:

• Lossy compression, like JPG. It permanently discards detail your eye is unlikely to miss in exchange for much smaller files — ideal for photographs. You control how aggressive it is with a quality slider.
• Lossless compression, like PNG. It packs the data more efficiently without throwing anything away, so the result is pixel-perfect. Use it for logos, screenshots and line art with crisp edges.
• Transparency (an alpha channel) in both lossy and lossless mode. This is a genuine advantage: PNG gives you transparency but large files, while JPG gives you small files but no transparency. WebP gives you both at once.
• Animation, as a modern replacement for GIF. Animated WebP supports full 24-bit colour and smooth transparency, where GIF is limited to 256 colours and hard-edged, on/off transparency.

No other single format in common web use covers all four.

WebP vs JPG vs PNG vs GIF: the full comparison

Here is how WebP stacks up against the three formats it was built to replace. The last two rows are where it earns its keep.

The typical size savings, based on Google's published benchmarks and what you will see in everyday use:

• Lossy WebP vs JPG: about 25–34% smaller at the same visual quality.
• Lossless WebP vs PNG: around 26% smaller on average, and often far more for flat, simple graphics.
• Animated WebP vs GIF: frequently less than half the size — with full colour instead of 256.

A worked example: what WebP saves on a real page

Numbers make the difference concrete. Imagine a photographer's portfolio page with 15 gallery images.

Exported as JPGs at 82% quality, the photos average about 280 KB each, so the gallery weighs roughly 15 × 280 KB = 4.1 MB. Re-saved as WebP at a matched quality, the same photos average around 185 KB each — a total of about 2.7 MB. That is a saving of 1.4 MB, or 34%, for images nobody could tell apart in a blind test.

What does 1.4 MB mean for a visitor? On a middling mobile connection of about 5 Mbps (roughly 0.6 MB per second), the image download drops from around 6.5 seconds to 4.3 seconds — more than two seconds faster, and most of that saving lands before the largest photo finishes painting, which is exactly what Google's Largest Contentful Paint metric measures. Add the site's logo — a flat-colour PNG that shrank from 240 KB to about 90 KB as lossless WebP — and the whole page gets meaningfully lighter for free.

How to open a .webp file

A .webp file that will not open is the most common reason people go looking for answers, so here are the reliable options, easiest first:

• Any web browser. Drag the file onto an open Chrome, Edge, Firefox or Safari window, or right-click it and choose "Open with" your browser. Every modern browser displays WebP instantly — nothing to install.
• Windows 10 and 11. Double-click the file to open it in the Photos app, which has supported WebP for years; File Explorer even shows thumbnails.
• macOS. Double-click to open in Preview, or select the file and press the spacebar for a Quick Look. Both have handled WebP since macOS 11 Big Sur (2020).
• To edit it. GIMP (free), Adobe Photoshop 23.2 or later, and Affinity Photo all open and export WebP natively. Older Photoshop versions need the free WebPShop plugin.
• Phones. Android has opened WebP since version 4.0; iPhones display it in Photos and Safari on iOS 14 and up.

If a specific, older program still refuses the file, do not fight it — convert the WebP to JPG or PNG first, then open that.

How to convert to and from WebP

Converting is quick and, with the right tool, completely private. The direction you go depends on your goal.

To convert to WebP (to shrink files for a website)

1. Open an image converter and load your JPG or PNG.
2. Choose WebP as the output format.
3. Pick lossy at around 80% quality for photos, or lossless for logos and graphics with sharp edges or transparency.
4. Save — you will usually see the file shrink by a quarter to a third instantly.

To convert from WebP (because something can't open it)

1. Load the .webp file into the converter.
2. Choose JPG for photographs, or PNG if the image has a transparent background you need to keep.
3. Export at 85–90% quality if you pick JPG, to keep the conversion invisible.

Our free image converter does both directions entirely in your browser — your pictures are never uploaded to a server, which matters for client work, personal photos or anything confidential.

When to use WebP — and when not to

WebP is the sensible default for almost anything you publish online, but it is not the answer to every situation.

Use WebP when:

• You are putting images on a website and want faster pages and better Core Web Vitals scores.
• You need transparency without the file-size penalty of PNG.
• You want an animation that looks far better than a GIF at a fraction of the size.

Reach for something else when:

• You are sharing with someone on old software, or emailing a non-technical recipient — a plain JPG or PNG avoids "why won't this open?" replies.
• You are preparing files for print. Print workflows expect TIFF, JPG or PDF, not WebP.
• You need HDR or 10-bit colour. WebP is limited to 8 bits per channel; for those cases the newer AVIF format is a better fit.
• You are archiving a master copy. Keep an untouched original (or a lossless file) and treat WebP as a delivery format, not your only copy.

Browser and device support in 2026

WebP support is no longer something to worry about. As of 2026 it works in roughly 97% of the browsers people actually use. The rollout timeline tells the story:

• Chrome and Opera: since 2011, right from the start.
• Microsoft Edge: since 2018.
• Firefox: since version 65 in January 2019.
• Safari (macOS and iOS): since version 14 in September 2020.

That last one mattered most — once Safari joined, WebP became safe to use as a website's primary image format for the vast majority of visitors. The small remainder are almost entirely people on very old, unpatched systems. If you need to cover them, the standard approach is an HTML <picture> element that offers a JPG or PNG fallback alongside the WebP, so old browsers quietly get the format they understand.

Frequently asked questions

Try the free tool — in your browser

You can switch any image to or from WebP in seconds with Imagloo's free, private tools. Everything runs locally in your browser, so nothing is ever uploaded:

• Image Converter — convert JPG or PNG to WebP, or turn a .webp back into JPG or PNG.
• Image Compressor — shrink any image, including WebP, to the smallest sensible size.