Why your iPhone keeps getting WebP files
You long-press an image in Chrome on your iPhone, tap Save, and the file that lands in your downloads ends in .webp - a format half your apps shrug at. This is not a setting you can change: the browser saves whatever format the website serves, and websites serve WebP because it is 25-34% smaller than JPG at the same quality. Smaller files mean faster pages and cheaper bandwidth for them; a mystery format for you.
The friction shows up everywhere. The image will not set as wallpaper properly. An upload form rejects it. You try to attach it to an email and it arrives as an oddity. Converting WebP to JPG on iPhone is the fix, and you do not need an app for it - modern Safari decodes WebP natively, so a web page can do the whole conversion on your phone.
How to convert WebP to JPG on iPhone (no app)
- Open this page in Safari. No App Store download, no account, no setup. Chrome on iPhone works too.
- Tap Select and pick your WebP. Choose from the Files app (where downloads land) or your Photos library. Add several at once if you have a batch.
- Hit Convert to JPG. The conversion runs entirely in the browser on your iPhone - your photos never upload to any server.
- Download the JPG. It saves to Files > Downloads. Open Files, tap the JPG, hit share, and Save Image to move it into Photos - or upload it straight to the form that rejected the WebP.
Compare that with what the guides suggest: install a third-party converter app (and hope it is not ad-ridden), build your own iOS Shortcut (works, but you maintain it), or upload to CloudConvert (25 free conversions a day, and your photo sits on their server). The browser route asks nothing of you.
iOS 16's built-in trick (and its limits)
Fairness demands mentioning Apple's own answer: on iOS 16 and later, open the WebP in the Files app, long-press it, choose Quick Actions > Convert Image, and pick JPG. It works - with limits. It only works from the Files app (not directly from Photos), it converts one image at a time, and you get Apple's size presets rather than your choice of quality. For a single stray image it is fine; for a batch of downloads, converting them all at once here is faster.
WebP vs JPG on iPhone - when to convert
WebP is the better storage format: smaller files, same looks. JPG is the better sharing format: it opens in every app, uploads to every form, attaches to every email, and prints everywhere. The sane workflow is convert-for-purpose: keep the WebP if you are just hoarding images, convert to JPG the moment something needs to accept the file. A converted JPG runs about 25-35% larger than the WebP it came from - that is the price of universality, and it is worth paying when compatibility is on the line.
Does it work on Android too?
Yes - the same page runs in Chrome on Android with the identical flow: pick the WebP, convert, download. (Some guides suggest screenshotting the WebP as a workaround. It works, but screenshots are lower resolution than the original and capture your UI chrome - converting properly takes the same ten seconds.)
The bottom line
WebP is not going away - the web is only serving more of it. Keep a no-install converter in your Safari bookmarks, convert at high quality, batch the downloads instead of fighting them one by one, and save the JPGs where the apps that need them can find them.