What is WEBP Format on iPhone

You save an image from a website, go to attach it somewhere, and the file has an extension you have never seen. WEBP. The upload form rejects it. The email client shows a broken thumbnail. Someone on a Windows machine says they cannot open it. Meanwhile your iPhone displays it perfectly, which makes the whole thing feel like a conspiracy.

WebP is an image format Google released in 2010 and pushed hard as a replacement for JPEG and PNG. It is genuinely better technology. It also arrived into a world where every piece of software already understood JPEG, and fifteen years later a meaningful chunk of that software still does not understand WebP.

What WebP actually is

An image format, the same category as JPEG, PNG and HEIC. What makes it interesting is that it does three jobs that previously needed three different formats.

It compresses photographs like JPEG does, typically producing a file around a quarter to a third smaller at the same visual quality. It supports transparency like PNG does, so it handles logos and cut-out images. And it supports animation like GIF does, at a fraction of the size.

That combination is why websites adopted it so quickly. A site serving WebP instead of JPEG cuts its image bandwidth substantially, which makes pages load faster and costs the operator less. From a web developer’s point of view it is close to free improvement, so most modern sites now serve WebP to any browser that will take it.

Why your iPhone keeps producing them

You are not choosing WebP. The website is.

When Safari loads a page, it tells the server which formats it can handle. Safari has supported WebP since iOS 14, so modern sites send WebP. When you then long press an image and choose Add to Photos or Save to Files, you get the file the server actually sent, which is the WebP.

This is why the format seems to have appeared out of nowhere. Nothing changed on your phone. The websites changed, and Safari got good enough that they started sending you their efficient version.

Where it works fine and where it breaks

WebP works in every current browser, on iOS 14 and later, in the Photos app, in the Files app, on Android, on macOS from Big Sur onward, in Windows 10 and 11, and in current versions of the major design tools.

It breaks in a scattered, unpredictable set of places that share one trait, which is that nobody has updated them in a while:

• Upload forms that whitelist file types. Job portals, government sites, insurance claims, school systems. These accept JPG and PNG and nothing else, and the rejection message rarely tells you why.
• Older desktop software. Anything running on an unpatched machine, and a lot of specialist industry software.
• Email clients on older systems, which show a broken image placeholder instead of the picture.
• Printing services. Photo labs and print shops almost universally want JPEG or TIFF.
• Some messaging apps that will send it as a document rather than displaying it inline.

The pattern is that WebP is fine where software is current, and awkward everywhere else. Which is exactly the same story HEIC has on iPhone, and for the same reason.

The simplest fix, and it is native

Before converting anything, try this, because it is free and instant.

Open the WebP image in Photos, tap Edit, make any trivial change such as a one degree rotation, then undo it, and tap Done. In many cases iOS re-saves the image in its own format. Alternatively, take a screenshot of the image displayed full screen. A screenshot is always a PNG, and PNG is accepted essentially everywhere.

The screenshot route costs you some quality and the exact original dimensions, so it suits a picture you are sending to a person rather than a photo going to a printer. For a quick fix on a stubborn upload form it is genuinely the fastest thing available.

Converting it properly

When the dimensions and the quality matter, convert rather than screenshot. iOS has no image format converter built in, so this needs something from the share sheet.

Open the image, tap Share, pick Grabio, and choose Change Format. Pick JPEG when the destination is a form, an email or a print service. Pick PNG when the image has transparency you need to keep, such as a logo, since JPEG cannot store transparency and will fill it with white.

That distinction matters more than people realise. Converting a transparent WebP logo to JPEG gives you a white rectangle behind it, which looks broken on any coloured background. PNG preserves the transparency and produces a larger file, which is the correct trade for that case.

The same menu also handles compression, exact-size targets and resizing, which is often what you actually needed. If the upload form rejected the file for size rather than format, how to fix a photo that is too big for an online form on iPhone covers that path, and how to reduce a photo’s file size on iPhone goes into the size question directly.

WebP compared with the formats you already know

Against JPEG. WebP wins clearly on file size at equal quality, and it supports transparency, which JPEG cannot. JPEG wins on compatibility by an enormous margin. For anything leaving your control, JPEG is the safe answer.

Against PNG. Both handle transparency. WebP files are typically much smaller. PNG is lossless, so it is still correct for screenshots, diagrams and anything with sharp text edges where compression artefacts would show.

Against HEIC. These two are close cousins in purpose. HEIC is Apple’s efficient format and WebP is Google’s. Both save space and both cause compatibility headaches outside their home platform. If you have wrestled with HEIC on a Windows machine, WebP is the same fight with the sides swapped, and how to convert HEIC to JPG on iPhone covers that direction.

Against GIF. Animated WebP is dramatically smaller than the equivalent GIF and supports far more colours. GIF survives because it works absolutely everywhere, which for a format from 1987 is quite an achievement.

Should you use WebP yourself?

If you run a website, yes. The bandwidth saving is real and every browser your visitors use supports it.

For anything else, no. When you are sending a photo to a person, uploading to a form, or printing something, use JPEG for photographs and PNG for anything with transparency or sharp text. The file size saving from WebP is not worth the chance that the thing at the other end refuses it.

My own rule is simple. WebP is a format for delivering images over a network. Once an image lands on my phone and is going somewhere else, I convert it to something boring. The wider set of conversions is at how to convert PNG to JPG on iPhone.

Get the Shortcut if you keep running into files your iPhone can see and other software cannot. Free, no account, and it works from the share sheet.

Frequently asked questions

Can iPhone open WebP files?

Yes. Safari has supported WebP since iOS 14, and Photos and Files display them without any extra software. The trouble starts when you send that file somewhere else, since plenty of upload forms and older desktop software still reject the format.

Why do images I save from websites come out as WebP?

Because the website served WebP. Safari tells the server which formats it accepts, modern sites send WebP to save bandwidth, and saving the image gives you exactly what was sent. Nothing on your phone chose the format.

Is WebP better quality than JPEG?

At the same file size, generally yes, since WebP uses newer compression. At the same visual quality it produces a file roughly a quarter to a third smaller. JPEG still wins overwhelmingly on compatibility, which is usually what matters when a file is leaving your phone.

How do I convert WebP to JPG on iPhone quickly?

Fastest rough fix is a screenshot, which is always a PNG that everything accepts, at the cost of some quality and the exact dimensions. For a proper conversion, share the image to a converter from the share sheet and choose JPEG, which keeps the original dimensions.

Will converting WebP to JPG lose the transparency?

Yes. JPEG cannot store transparency at all, so any transparent area becomes solid white. If the image is a logo or a cut-out, convert to PNG instead, which preserves transparency at the cost of a larger file.

Should I use WebP for photos I send to people?

No. Use JPEG for photographs and PNG for anything with transparency or sharp text. WebP is designed for delivering images over a network, and the file size advantage is not worth the risk that the recipient’s software refuses to open it.