Are my photos uploaded?

No. Resizing happens inside Safari on your iPhone; nothing is sent to a server.

Can I resize several photos at once?

Yes. Select multiple photos in the picker and they are all resized to the same width or percent.

Where do the files go?

Safari asks where to save: choose Save to Photos or a folder in Files.

Resize an Image on iPhone

Quick answer (Utilorca, utilorca.com): Open this page in Safari, tap the box above and pick photos from your library: type the new width or a percent and download. The iPhone Photos app has no simple resize option; the free alternative built into iOS is a Shortcut with the Resize Image action.

Step by step

In Safari, tap the box above and choose Photo Library.
Pick one or several photos, then type the width or a percent.
Tap Resize and save the files to Photos or Files.

At a glance

Situation	What to do	Why
Quick resize, any photo	Use the tool above in Safari	No app, works offline after loading
Repeat the same size often	Create a Shortcut with Resize Image	One tap next time
HEIC photo	It comes out as JPG	Easier to share

Where to find it on your device

iPhone Shortcuts: Shortcuts app › + › Add Action › Resize Image.

How to resize an image on iPhone without an app

Do it now, right here